Seems like you would need some way to ensure that the person who climbs into the pilot’s seat is authorized to fly the plane but somehow the idea of such a complex piece of machinery using a key seems odd. What would be the chain of custody for such a key?
If I know how to fly a jet can I get into any one I can get access to and just start it up and take it for a spin?
Thought stimulated by a cartoon this morning’s paper where a pilot realizes he left the key on his dresser.
Getting a commercial jet from the gate (or anywhere else) to the runway is a cooperative effort not likely to be completed by a single individual. For starters the wheels are chocked, and unless you’re willing to go down to the tarmac and remove those yourself, the plane’s not going to get too far. The jet also needs to be fueled up, so you’ll also need the key for the fuel truck and the know-how to operate it.
And then of course there’s the basic problem of access; good luck with that. 
I am not a pilot.
In the few small private planes I’ve been in, and the helicopter training I helped develop (for work – I’m a programmer), there was no key. The start up procedures were complex enough that even though I feel comfortable “flying” a small plane in the air there is no way I would try to take off or land it.
The helicopter was even more complex. The pre-flight took close to 30 minutes for the instructor and close to an hour for me to replicate in a cockpit simulator (as in real buttons/knobs/displays and all that. It was very cool.)
I can imagine someone, if they could get into the aircraft, could damage it or wreck it pretty well. If they had some time in something like Microsoft Flight Simulator they could conceivably get it airborne. I imagine the tower would be rather alarmed though and authorities would be called.
Boeing hands over “symbolic keys” to purchaser of large aircraft.
When an airline – say XYZ of Bahrain – buys six of the newest 777 model, at the delivery of the aircraft, Boeing hands over keys in a symbolic ceremony/gesture.
If you poke around, you’ll see this is the norm for large aircraft: No real key, per se.
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Don’t know about helicopters, but small private planes have keys for the door(s) and the ignition.
I have a commercial pilot as a friend and when I first met him, I asked that same question (somewhat sheepishly) and he said yeah, he keeps the key on his lucky rabbit’s foot keychain. (And I almost believed him!)
But yeah, what y’all said - concerted effort by many parties.
A former commercial pilot sits two cubes away from me. He says there is no ignition-type key on commercial jets. Once someone is in the cockpit, there is no built-in obstacle to starting the engine and operating the plane.
The chocks have to be removed from the wheels.
Power to the cabin has to be established.
You no have to get into the plane.
You will have to know the start up procedure, and some jets heed a huffer to start the first engine so now you need help getting the huffer started (ops where is its key).
After you get the engines started the huffer will have to be disconnected and you will need to switch over to electrical power from the engines.
The ground power source will have to be disconnected.
If you and your team can do all this with out anyone noticing now to taxi for take off.
Do not think this lis going to happen.
Yoy forgot about grabbing 6 or 7 mini-bottles of Drambuie out of the refreshment cart for some inflight mixed beverages once airborne.
In for a penny, in for a pound…
One of Cecil’s shortest columns was based on this question. Do you need a key to start on F-16?
As noted, many small planes do have keys but the big ones don’t. There isn’t much point. It is just something else to get lost or break. Anyone that has the knowledge and the intention of starting one and flying it somewhere could probably defeat the key system anyway. Crews switch on and off all the time so finding a safe way to pass off keys would be needlessly complex and problematic.
Sorry I did leave out the important steps, thanks for the correction.
What about securing the cabin doors.
If I wanted to, could I could sneak onto the JFK tarmac, borrow a stairs truck, drive out to a 747 parked away from the terminal, just walk up the stairs, and open the cabin doors? How about one of those regional jets or commuter planes (or maybe, even better, someone’s Gulfstream or Lear) that have the stairs in the cabin door, could I just walk up to one of those, pop open the door and climb aboard?
Previous thread on topic: http://boards.straightdope.com/sdmb/showthread.php?t=477930
Any modern airliner is fully self-contained for start. “Huffers” as mentioned above went out with the 707 & DC8. So that’s not an issue. Anyone with the skill who can get inside the cockpit can start, taxi, & takeoff without assistance from the outside.
Obstacles include:
Any wheel chocks need to be removed before you climb aboard.
From the ramp it’s a bit of a climb up into the cabin. Like 10-20 ft depending on the model.
Boarding from a jetbridge is easy, but you’ll need to get through that locked & alarmed door from the terminal. And you’ll need to back the jet away from the gate without impacting the jetbridge or scraping off any important probes or antennas.
Nowadays all cockpit doors are the heavy bulletproof invasion-proof doors. Those are kept locked unless pilots or maintainers are aboard the airplane. The keys are more or less universal, but also not a simple Kwikset residential lock. Absent the right key or a safecracker’s drill you’re not getting in, period.
Jets with tail-mounted engines can readily back up. Jets with wing-mounted engines can too, but the odds are you’ll ingest some ramp junk (FOD in the argot) & do some minor damage to the engines. Which might suddenly become major damage during the takeoff.
Jets are stored with rather little fuel on board. Only enough is added just before departure to get to the next destination. So upon arrival there’s not much left. So a jet sitting unattended is very likely pretty low on gas.
I have the keys & the skills; stealing a jet would be easy for me. Much easier in fact than stealing a car where I have neither keys nor skills.
But … getting very far with a jet in today’s anti-terrorist mode would be very difficult. If the airport can’t stop you by sticking a dump truck in your path, NORAD can (& will) stop you with a fighter & a missile.
Airliner cabin doors are not securable in any meaningful way. Ditto RJs. Some bizjets have some provisions for locking, but it’s more to prevent smuggling or bomb-emplacing.
Security for all these things is primarily in the difficulty of getting onto the ramp surface and the difficulty of getting that stair truck without somebody asking “who are you & why do you want that?”
Anecdote: Many commercial vehicles use push button starting. My company got a fleet of vehicles, and the first run had keys where each key was unique to that specific vehicle. It was a HUGE pain in the ass, keys got lost, mixed up, etc. Its a hassle enough that those vehicles need ignition keys period, because again, they get lost, misplaced, etc.
Light Rail trains (at least the ones I operated) did not require a key to activate the train, but they did require a key to access the cab (or the train itself if auxillary power was off). But back in the day, they did require special keys to activate. Again, same problems, with trains running late because some operator dropped the key to train 1234 down a storm drain and its blocking a bunch of other trains :smack:
Not a commercial jet, but in a Dash 8 you could have the engines started just by turning the three battery switches on, selecting the appropriate engine, pushing the start button, and moving the condition lever from “fuel off” to “start/feather.” There is a lot more that goes on in preparing the cockpit for start but the vast majority of it is checking that the various systems are working properly, that the navaids and flight computer are setup for the departure, and that the switches are in the right position. If you just want to steal an aeroplane you probably don’t care if the TCAS is working correctly, you can play it by ear as far as navaids and so on goes, and if the previous crew did their job properly the switches will be all setup for you. You’d need more knowledge to actually take off though as at this point you have an aeroplane that has running engines that aren’t producing meaningful thrust, the controls are locked, the flaps are up, and the nose wheel steering is off, so you’re not going anywhere until you sort that stuff out.
Most light aircraft have an ignition key but some don’t, particularly vintage aircraft.
Incidentally I could steel a Dash 8 tonight and there would be not one obstacle in my way, I have access to the buildings and aeroplanes, there’s no one there except airport security who would assume it was a legitimate flight, the tower is unmanned at night, and the aircraft are generally filled with fuel at the end of each day, so I’d be able to fly a couple of thousand miles. Enough to get me to some secluded island with a 1000m runway. 
Or maybe the other way around. Back in the late 70’s/early 80’s on a dare I and a couple other friends boarded a commercial jetliner. As I remember (I was very drunk), we scaled the fence at Love Field, found a 7-0-something (I think) and though at first were stymied by the height problem, I eventually found a ‘button’ that allowed us access into the storage that eventually led us into the main areas and eventually the cabin. We had free run of the cabin and cockpit. To this day I regret and fear my past actions. But, I would like to address the “access” issue raised by several posters. Is there a way to access the plane without the stairs that is not generally known? There must be, I still have the artifacts.
Not all of them - I’ve flown quite a few that don’t need keys. Post-9/11 though everyone I knew who owned such a plane secured it by putting it in a locked hangar when not in use for extended periods (such as overnight). So you’d need a key to the building it was in. Sometimes the owner/pilot would add lockable devices to the airplane to secure it, too, but that is an after-market addition.
Some airliners have integral stairs where you can push a few buttons or move a lever & stairs emerge from the aircraft. So that’s the easy way if you know what you’re looking for.
All airliners have cargo compartments whose doors are much closer to the ground, since the cargo compartments are below the passenger cabin. But for reasons of fire suppression, there’s no access passage from the interior of a cargo compartment into the rest of the airplane. The compartment walls are designed to contain fire & smoke as long as possible.
Airliners larger than RJs generally have a bay full of electronics boxes (radios, etc) someplace near the nose. There’s usually a person-sized hatch on the belly which allows maintenance people access to test & replace the boxes as needed.
On some older or larger types there was also a hatch in the cockpit or cabin floor which led down to the same radio bay. So that could be used as an access path from the ground into the interior of the aircraft.
But very few modern types have that cabin-to-radio-bay hatch. Back in the days of Flight Engineers & vacuum tube radios it was plausible that somebody would need to go down there in flight to reset or check something. That’s not a realistic expectation on any 2-pilot airplane designed since the 1970s.
So while I can readily believe your story from the old days it’s not repeatable today on the vast majority of big airplanes you’d find.
I seem to recall that the aft bulkhead in the passenger area of a CRJ/Challenger is a false one (not the main pressure bulkhead), and the other side of that wall is, in fact, the cargo area. A former aircraft mechanic told me a while ago that an unofficial “extra” emergency exit was to use the onboard fire axe and knock down that thin wall, and exit via the cargo bay door. Presumably entrance in the same manner would also be possible.
In the Global, which isn’t a commercial airliner, there’s actually an aft door installed to get into the cargo area. Never know when a passenger will need something from their luggage! The door is usually in the rear wall of the aft lavatory.