Not much in the way of specifics to add to the excellent posts already. But to put some perspective on the overall picture, at least in the US …
In non-hub non-major cities the traffic is sparse enough that each airplane is mostly able to fly the speeds & climb & descent rates which best suit it. I can launch in my airliner just a couple minutes behind **Broomstick **in her Cessna. By the time I get airborne she’s turned out of my way & we each go our separate paths. Withing a minute I’ll be above & ahead of her & she’ll never catch me after that. So no traffic conflict.
If departing ahead or behind another jet, odds are our courses will diverge soon enough since we’re probably not going to the same place. We do sometimes get in a situation where we’re going the same way for at least the first 10-15 minutes and we have incompatible speeds, with the inherently faster airplane behind. The fast one will be slowed back by ATC, which in turn leads to a steeper climb. Meanwhile, the one in front will be asked to go as fast as practical. Which leads to a flatter climb for him/her. After a few minutes enough altitude separation exists that both can resume normal speeds with the fast airplane above the slower one ahead. The courses eventually diverge & the problem is solved.
At busy hub or big city airports it’s typical that ATC develops different prescribed departure paths for 3 classes of aircraft: light planes, turboprops, and jets. The jets tend to be the only group which has both enough traffic density and enough speed disparity that it becomes an issue for ATC to manage speeds. If so, the departure path procedures will dictate specific speeds at various points which are generally compatible with typical bizjet / airliner speeds. If everybody sticks to the procedure speeds separation will largely take care of itself.
If the OP is looking for ballpark climb speeds to be realistic when simming, something in the 280 to 320 KIAS range would be good for any jet. In the mid-high 20s altitude range, switch from flying IAS to flying Mach. You’d normally do the high part of the climb at whatever your cruise Mach will be. That can be anywhere from M0.74 to M0.90 depending on the aircraft type. Absent any other info, M0.79 will work well enough in any jet. As a general rule, the faster the cruise Mach, the faster the IAS climb speed should be also. E.g. flying a Citation I biz jet which cruises at M0.73 will probably climb at 280 until reaching M0.73 them maintain that Mach up to cruise altitude. A 747-400 which cruises at M0.85 will probably climb at 320 until reaching that M0.85 then maintain that to cruise altitude.
Descent, arrival, approach, and landing are conceptually similar. In high density environments the published procedures are very prescriptive & everybody ends up traversing close to the same path through space and at the same speeds. At low density airports there’s a lot more freedom to fly the best descent profile & speeds for your particular airplane.
The typical decent is flown just like the climb but in reverse. Pull the power to idle, maintain cruise Mach until intercepting the IAS you used for climb-out, then maintain that IAS until it’s time to slow for 10,000’ (see below) and then for landing. You pick the *place *to start descending so that idle power plus those speeds puts you in the right spot in the sky to make the landing with as little added power as possible. At least that’s the ideal. In any environment with traffic, ATC will descend you early and you’ll end up descending and or driving around at lower altitudes at partial power to reach the field.
Speaking strictly to the last few miles before landing …
ATC’s goal is to have airplanes touching down every *X *seconds, as close together as will get one pulling off the runway shortly before the other one lands. *X is typically about 60 seconds. So upstream the enroute ATC’s job is to get the jets spaced out at about 2X *second intervals when we’re going a lot faster & as everybody slows, the space between airplanes compresses along with the time.
At moderately busy airports it’s common to have ATC control your speed up to the final approach fix (FAF) generally about 5 miles short of the runway. As **Richard Pearse **said above, there’s a speed limit of 250 KIAS below 10,000 ft, so everybody is already doing that speed once down below 10,000’. During pattern manuevering it’s typical to slow to 210 or 200. Another common retriction from base and onto final is to maintain 170 or 180 KIAS until the FAF.
Beyond that point it’s necessary to aggressively slow and quickly finish lowering gear & flaps to get down to landing speed before you get too close to the runway. So ATC is hands-off in that segment. If they allowed enough space ahead of you it will all work out. If not, the end result is a go-around for the trailing airplane when he/she gets to the threshold & the preceding airplane is not yet off the runway.
Half the fun of airline flying is trying to manage your descent to use the minimum possible power (& hence fuel) all the way from cruise a hundred miles from the airport, through all the ATC speed / altitude wickets on the way down and all the way to short final: on speed, in position and properly configured. The ever changing winds all the way down always add some wildcards to the game.