Wow, never meant to create such controversy! I’m afraid that given the brief view, my fallible memory, and the plausibility of the suggestions, all of them seem possible candidates. I’m afraid this may remain a mystery.
Moderator Note
Don’t bring in an argument from an entirely unrelated thread. Let’s drop the hijack.
Colibri
General Questions Moderator
As soon as I read ‘I noticed it had squared off wingtips, a blunt nose with a pronounced cowling around the engine, and white army stars painted on the underside of each wing’, I thought ‘T-6 Texan.’ I see that Gorsnak already posted the link I was going to post.
Here’s a plan view of the Texan that shows the square wingtips and, of course, the round cowling over the radial engine. The T-6/SNJ is a ubiquitous ‘warbird’. They’re relatively inexpensive – you can get them for well under $200,000. Most people who own a warbird paint them in military schemes, so the stars make sense for just about anything from that era.
Anyway, I think the description and availability make the T-6/SNJ the most likely plane you saw.
Speaking of North American warbirds, check this out:
1944 NORTH AMERICAN XP-82 TWIN MUSTANG For Sale in Titusville, Florida | Controller.com
One of the most remarkable warbirds flying today. The prototype North American XP-82 “Twin Mustang”. The XP-82 is one of five surviving P-82 Twin Mustangs and is currently the only one flying and one of two in civilian ownership.
If you happen to have an spare 12 megabucks lying about…
The F4U Corsair also had a massive radial engine and squarish wingtips. Not as squared-off as on the Grumman cats, but not as round as, say, on a Japanese Zero either.
I was once surprised by one of these taking off from the airport in Madison, WI. At first, all I could hear was the engine noise, and it took a couple of seconds for me to realize it was no ordinary engine. It sounded like a buzz saw, or a hornet/wasp on speed. I turned around and saw this magnificent airplane emerge from over the treetops. It was a moment I’ll never forget!
Interesting anecdote about massive radial engines and the F8F Bearcat in particular:
I once knew a woman who had been a WAVE at a US Naval Air Station back in the '50s, when the F8F was still around for non-combat duties. She was showing a group of deaf schoolchildren around the station and got a pilot to fire up the Bearcat’s engine for them.
The children started crying with joy. They were hearing something for the first time in their lives!.
I just thought of this: It was unusual to have US national insignia on both wings after the first part of 1942. They were normally applied to the left wing only, supposedly to present a more asymmetric target to the enemy.
Did the plane you saw have the red “meatball” inside its white stars? That would also place it prior to mid-1942 (they were abandoned because US pilots in the Pacific tended to shoot at anything red like a Japanese hinomaru).
If the plane was from early WWII, my guess would be that it was a Grumman F4F Wildcat, which preceded the Hellcat, the Corsair, and the Avenger.
Or a Double Wasp, maybe? 
I was at WJF one day when a Corsair took off. (I think it was Bill Barnes, son of Pancho Barnes, flying.) I was 3,400 feet away, and I could feel the engine. It literally shook the ground.
A very cursory search indicates there are 16 airworthy Wildcats in the U.S. FWIW, there are about 27 airworthy Corsairs, 13 airworthy Bearcats (2 civilian-built), 6 airworthy Hellcats, 13 airworthy Thunderbolts, and 33 airworthy Avengers. I was unable to find how many T-6/SNJs there are flying, but I wouldn’t be surprised if the number was in the hundreds.
My guess is still that the OP saw a T-6/SNJ.
I think it unlikely it was a P-47; they had wings shaped like orange segments, more like the Spitfire.
The propeller tips can actually go supersonic in F4U’s (just the tips) which make a cracking sound…
To all the good questions asked of the OP thus far I’d ask where this aircraft was seen. (No need to give too many details.) For example, near Reno, NV one might expect to see an F8F modified for air racing, etc. Or Oshkosh WI or Abbotsford BC, could be part of an airshow.
Enough that in the 1970 movie, Tora Tora Tora! T6s substituted for Zekes and modified T6s for Kates.
.jpg){kind=link}
Did you know that there’s an Internet Movie Plane Database?
The Commemorative Air Force Museum in Mesa Az offers rides in a T-6 Texan that’s painted in Navy blue colors. It would be in the air a lot, so if this was anywhere near there, that could be it.
The T-28 (also sometimes AT-28) is another good possibility. More rare than a T-6, but more square and fighter-like. The T-6’s wingtips are not square. They’re not semicircles, but they’re distinctly rounded. As is the horizontal and vertical tail. The T-28 is much more rectangular overall. The T-6 has long-ish trainer wings, not stubby broad-chord fighter wings like the T-28.
I live five miles from Falcon Field but at $360 a flight I’m too cheap. However when my nephew was a teen my brother popped for a flight on his birthday. You shoulda seen the grin on his face when the flight was over.
Avgas is… what? Six dollars/gallon? A T-6 burns something like 30 gph. So that’s $180/hour just for fuel. I’ve heard radial engines tend to use a lot of oil. I don’t know how much that costs. As they’re charging for flights, they would have to pay for 100-hour inspections plus the annual inspections (the annual counts as a 100-hour). Then there’s hangar space, insurance, routine maintenance, and overhauls that also have to be figured into the hourly cost. Not to mention the cost of the pilot.
But $360 for one-third of an hours does seem a bit dear. If I could afford it, I’d chalk it up to a ride in an expensive-to-operate aircraft plus a nice donation to the museum.
Oh, I didn’t mean to imply I was begrudging them the money, just that my light-weight wallet won’t stand for it well.
Mine neither. 