Factual error: Towards the end there's a firefight between Matrix who wields a shotgun and El Presidente who is armed with a Steyr AUG. The weapon sounds used for the Steyr AUG however are from a MAC 10 or an UZI and don't sound a bit like it.
Factual error: The shot of Matrix landing in the swamp after jumping from the plane isn't consistent with the free fall. The final shot indicates he has not fallen more than a couple meters. On top of that, after jumping from a DC-10 doing over 150 mph, he has no forward momentum when he lands.
Factual error: If the access hatch to the nose wheel well on an airliner was opened at any time during the flight, every alarm panel in the cockpit would light up like a Christmas tree. In this case happening within seconds of takeoff the pilot would immediately declare an emergency, turn around and land at the airport he had just left.
Factual error: The explosives that Matrix places by the buildings on the island are Anti-personnel Claymore mines. You can see on the back, it says "APERS MINE" (APERS MINE = Anti-Personnel Mine). They spray out steel balls designed to take out enemy troops. The relatively small amount of explosive in them is used to propel the steel balls to lethal speeds. There's nowhere near enough explosive in them to demolish those buildings the way that was shown in the movie. In regards to the point about explosives being inside the buildings and being "ignited by the blast of the mines". There's no way Matrix could have known about the explosives inside the buildings. He was OUTSIDE the buildings, so he would have no logical reason to place the explosives there. Also, some of those buildings were barracks for the troops. There would not be explosives stored in them.
Factual error: As noted elsewhere, it is simply not credible that Cindy, a trainee pilot, could land an seaplane so neatly, but it should also be pointed out that she banks into a low level formation on three helicopters - a very tricky manouevre, and then immediately after take off banks tightly into a high speed flyover of the squad on the beach. Both of these stunts would demand a very high level of skill from a pilot, especially one flying a lumbering old seaplane.
Factual error: A DC 10-10 (the Western plane that Matrix is forced to board) has a fully-loaded maximum range of 3,800 miles, but an 11 hour flight into South America would be closer to 6,000 miles. Even if the plane flew empty, it would barely be able to cover that distance, and many passengers and pallets of cargo are seen on board.
Factual error: Matrix reads coordinates N33° 13' W117° (or possibly W119°) 18'. Neither LAT or LONG has seconds; just degrees and minutes, but he says, "These coordinates are somewhere near Santa Barbara". Even if you fill in 59" for the latitude north, it's still quite a ways south of Santa Barbara. If you fill in 119° it takes you farther west out to sea: that much further from Santa Barbara. The closest island to those coordinates is San Nicolas Island, and since they did go to an island later, that must have been it. Still a far cry from Santa Barbara. The handwritten coordinates would be much easier to read on Blu Ray.
Factual error: Rae Dawn Chong sees a receipt for some aircraft fuel and comments that its "type 4" the kind used for amphibian aircraft. Well I've not heard of "type 4" and surely fuel used is differentiated by the type of engine not by the type of aircraft, JP4 is kerosene for jet engines and avgas for piston engines. (The plane they take has piston engines).
Factual error: When Cindy and Matrix are in the warehouse, Cindy instantly knows that 250 gallons would get the plane to the island and back. It would be unlikely that she knows the rate of fuel flow, and, indeed, the weather conditions and type of engine, to allow her to figure this out.
Factual error: When Cindy approaches the security guard to report Matrix, the guard calls backup. There is no antenna on his radio.
Factual error: When Cindy first gets into the seaplane, she asks 'where are the LCD readouts? - I learned in a Cessna' as well as saying 'this plane is older than I am.' Any Cessna she learned to fly in would almost certainly be older than her, but even worse, Cessnas used for initial flight training (150s, 152s or 172s) certainly do not have LCD displays.
Factual error: Arnie drops from a plane travelling well over 100mph, falls about 100 feet, and just because he lands in a marsh, doesn't mean he'd be uninjured...
Factual error: When Matrix drives the car head on into the telephone pole, he gets out of the car with no injuries. It looks like he was driving at least 40 miles per hour. They weren't wearing seatbelts either, so both of them should have flown through the windscreen.