Factual error: Before "classes" begin, the pilots are told that they would be flying against planes that are faster than their F-14's. The F-14's top airspeed is over 500 mph faster than the F-5's, and more than DOUBLE that of the A-4.
Factual error: In every scene in which Maverick and Goose are in their flight suits, the squadron patch they wear is that of Airborne Early Warning Squadron One Two Zero (VAW-120). The same graphic is use on their flight helmets. Airborne Early Warning Squadrons in 1986 were flying the E-2C Hawkeye, a twin-turboprop aircraft with a rather large and obvious 24' diameter rotating dome mounted above the fuselage. Also worth noting, the squadron logo used on the aircraft in the movie was that of Strike Fighter Squadron 25, the "Fist of the Fleet." VFA-25 never flew F-14 Tomcats. In 1968, they flew the A-7B Corsair II, then in May 1983 they transitioned to the F/A -18A Hornet. Additionally, Hollywood and Wolfman are wearing patches/helmet graphics of VAW-124 Bear Aces (another VAW E-2 squadron).
Factual error: In all sequences where Maverick "puts on the brakes", he is shown pushing the throttle quadrant forward and pulling the stick back. This would put him in a full-afterburner climb, but you don't really stop and it doesn't work in a medium speed tail chase (which is easier to film). The air brake does effectively nothing on the F-14 because it is too small, and not deployable at full power.
Factual error: During the briefing before the final scene, the Commander says, "The Migs carry the Exocet missile. They can fire that missile from a hundred miles away." Yes they could fire the Exocet from a hundred miles away, but the Exocet's maximum range at the time of this movie was around 40 miles. Plus the Exocet is a French missile and would not be on a Soviet Union fighter.
Factual error: All the scenes with actors in the cockpit were shot in the front cockpit. Pay attention to the canopy frame behind the RIO. This would also explain a large gaffe from the movie - Merlin taps on the fuel quantity indicator and exclaims "C'mon Cougar, we gotta land this thing, we are way low on gas." The particular fuel quantity indicator shown being tapped by 'Merlin' the RIO, the one with the vertical tapes, is present only in the pilot cockpit. The F-14A rear cockpit has only a small fuel totalizer.
Factual error: This is the most basic mistake of all, but probably only obvious to those who fly in the Navy. Almost every written reference to "TOP GUN" is wrong. TOPGUN is one word, all caps, always has been.
Factual error: In nearly every cockpit scene, regardless of fighter airframe, you can see that half or more of the lights on the caution lights panel on the lower right-hand side of the cockpit are lit. These lights are the illuminated names of all the systems that are not currently operating, ergo if the "Engine 1" light is lit, then Engine 1 is not running. If over half of the lights are lit (as in the cockpit scenes) then the pilots must be flying without half of their systems running, including engines, hydraulics, and radar. None of these lights should be on in flight. This makes it obvious that the scenes were shot on the ground using external power.
Factual error: Just as Mav goes into the flat spin, you hear a voice over while looking at the rear of his F-14 (you can see the AB), you hear "Engine 1 is out" and you see the right engine flame out... this is engine 2, engine 1 is the left engine.
Factual error: The final dogfight scene has a huge error when Hollywood's jet is hit with a missile and he ejects. The next scene shows him manually deploying a small pilot chute to open his main parachute. After seat/man seperation, the main chute automatically deploys depending on altitude and airspeed. He would still be connected to his ejection seat until his chute deploys. Having to manually throw a "pilot chute" to the wind would leave too much for human error.
Factual error: When Goose takes the photo of the MIG's cockpit, the type of Polaroid camera he is using has an acoustic auto-focus system. It will not focus beyond clear glass or plastic because the ultrasonic pulse bounces off the glass and not off whatever is behind it. Therefore the photo would be focused on Goose's own canopy and the MIG's cockpit instruments (of interest to Charlie) would be very blurry. Perhaps that is why the photo is not shown. Also: Goose proclaims the photo great immediately after it comes out of the camera. In fact it takes a minute or so to develop and become visible.
Factual error: The beginning of the movie when Maverick inverts and gets cozy (canopy to canopy) with the MIG pilot and Goose is taking pictures could never have happened. The tails of the F-14 are nearly 9 feet tall and the canopies are a mere three feet apart, so this would have resulted in a collision.
Factual error: When Top Gun first came out, everybody in our squadron made a big joke of the "Deadly Blue Tubes." This refers to the sidewinder missiles that were supposedly launched from the Tomcats. Those who are familiar with aircraft weapons, would know that the blue tube is a sidewinder simulator. If you were to launch this from the aircraft, all it could do is drop like a rock.
Factual error: Iceman is hit by cannon fire and has to shut down the right engine as a consequence. Later on, when Iceman and Maverick return to the carrier, Maverick asks for a flyby, which both tomcats perform as if nothing had happened to Iceman's plane. This violates regulation, essential safety protocols and it contradicts both Maverick and Iceman's personalities. The first thing you want to do when flying with only one engine (because your plane is damaged) is to make sure you land as soon as possible, you don't perform flybys, you don't even consider it. The remaining engine could fail too, turning the tomcat into a glider, that would mean the loss of the plane and it would put the lives of both pilots at even more risk. Maverick wouldn't allow this after losing Goose and Iceman has that nickname and reputation because he's a perfectionist, he plays utterly by the rules he wouldn't act like a fool when flying a damaged plane in that context. Also, Iceman performs that flyby with both engines running, which is absurd. (01:39:20 - 01:40:00)