Continuity mistake: When Jetfire tries to leave the James S. McDonnell Space Hangar and says, "I command these doors to open," there is a shot of Sam, Mikaela, Simmons and Leo standing at the tip of what was Jetfire's enclosure bars, looking up, a bit to their right as if Jetfire was directly in front of them. In the next shot Jetfire, who is way down at the end of the hangar, breaks down the door and heads out. Next shot, they're all still looking up in the very same direction, even though they should be looking all the way to their right, straight ahead into the distance. (01:23:40)
Continuity mistake: After Jetfire's transformation, when he snipes, "You little spinal-cord-based organisms," he knocks the Mercury capsule and it falls. In the shot facing Jetfire, as it rolls toward Sam and the others, Jetfire is no longer standing within his enclosure, he is actually to the left of it. However, in the next shot as the Mercury capsule rolls toward Sam, the teenager is standing directly in front of the enclosure's bars. (01:23:30)
Continuity mistake: At the aircraft 'boneyard', Sam uses a dagger to carve a huge circle of symbols into the ground, and in the first close-up Sam finishes up a specific symbol at the top of the circle, sticks the dagger in the dirt and stands up. In the next overhead wideshot, Sam is not only still kneeling and then stands up again, but he was actually kneeling at a different symbol located at the bottom of the circle. (01:25:50)
Continuity mistake: As Jetfire transforms, Simmons orders everyone to hide by the Mig, and as they run to it the tall lighting pole is positioned in the open area between Jetfire's enclosure and two red-trimmed glass showcases. But when Jetfire begins to ask, "What sort of hideous mausoleum is this?" that tall pole is now between the two showcases and there are metal posts with red rope suddenly surrounding it. Then when Jetfire breaks out of the hangar, the lighting pole and metal posts have all vanished. (01:23:05)
Continuity mistake: When Devastator is sucking up the vehicles and structures at the construction site, the large camper's exterior is pulled off, leaving only the frame as the camper is pulled forward, but a few shots later, in an overhead wideshot that camper is still intact and straight, as Mudflap and Skids stand firm. (01:56:55)
Continuity mistake: In Egypt, when Sam says, "We got cops!" they're at a fork in the road, and with two police cars heading towards them from the left of the 'fork', Sam drives to the right of the 'fork'. However, in the next shot, the two police cars are driving past Bumblebee and the twins on the very same road, just before the police cars make their U-turns. (01:35:55)
Continuity mistake: When Bumblebee is battling Rampage, there's a close-up of Bumblebee as he dramatically drops his yellow faceplate over his face. In the next shot, Sam is on the ground in front of the car on its side (Rampage overturned it moments before). Problem is in the next shot Mikaela is also in front of that very same car, but Sam is gone, and she wasn't seen in the previous shot of Sam either. (02:00:30)
Continuity mistake: When Bumblebee shows up at the frat party with the horn blaring, Sam looks outside and sees the car on the lawn flashing headlights with a clean front bumper, but when Sam questions Bumblebee, there are bush branches all over the bumper. (00:35:00)
Continuity mistake: When Alice is with Sam in the symbol filled dorm room, there is a large, twin, folding picture frame beside the bed, whose position changes from the right side to the left side of the windowsill, repeatedly. (00:51:20)
Continuity mistake: When Alice and Leo walk in on Sam's symbol filled dorm room, certain posters either suddenly appear on the wall, or vanish, or reappear ripped, between shots. (00:50:10)
Continuity mistake: When Leo and Alice walk in on Sam in the symbol filled dorm room, there are large yellow symbols on the closet door which are partially erased when he knocks over the microwave, then back to the way it was originally. (00:50:00)
Continuity mistake: When Grindor seizes the Saturn, Sam falls out of the door and in Mikaela's close-up Leo's arm hangs out of the rolled down back window, but in the next shot that window is rolled all the way up, only to be rolled down again in following shots. (00:55:10)
Continuity mistake: When the Decepticon meteors are heading towards the aircraft carrier, we can see several aircraft carriers. When the meteors land, only one aircraft carrier is shown, and the surrounding boats disappear.
Continuity mistake: In the scene where Captain Lennox pulls Mikaela from Sam after he has been blown away, you see her lying on the sand with the right side of her bra cup exposed but when you see her again her top is in the right position. (02:12:40)
Continuity mistake: When the Decepticons dive into the ocean to retrieve Megatron they are immediately spotted by a Navy submarine. The crew is reporting "five contacts" at this point. At the ocean ground they resurrect Megatron by killing one of their own mates and using its parts. After that they head back with Megatron to the surface. The crew is now observing "six hostiles" even though they left the killed Decepticon behind. (00:39:00 - 00:41:00)
Continuity mistake: At the end of the movie, the first shot of Sam and Optimus shows them standing on the deck of CVN 71 (pan in), yet after their conversation they are standing on the deck of CVN 74.
Continuity mistake: At NEST headquarters, when Galloway shows up and speaks via camera with General Morshower, he is seen on the monitor buttoning up his suit jacket, but in person his jacket remains unbuttoned. (00:22:25)
Continuity mistake: When Optimus jumps in the factory, during the overhead shot, Megatron also starts a flip. But Optimus nearly hits the ground at the end of that shot, while Megatron is only half-way through. Yet in the following shot, they both land at the same time.
Continuity mistake: When Megatron stabs Optimus through his back, Optimus' elbow is scratched, but clean. When Megatron lifts him, there are big chunks of grass on his elbow. (01:02:20)
Continuity mistake: When Lennox is trying to revive Sam, there is a close-up of the sock starting to slip out of Sam's grasp, but it's still in his hand. Then when the medics are using the paddles on Sam, clearly there is nothing in his bandaged hand. The problem is that there is another close-up of Sam's hand, after Mikaela professes her love, and the sock is still there in Sam's hand before it dramatically falls (it's the same close-up angle as the previous shot). (02:13:40)
Answer: After the tomb, he doesn't appear onscreen again. There's no indication as to what happened to him.
JAGwire