Chuck was lost in 1995, yet his Jeep Cherokee is clearly a 1999 model. The newly styled front end first appeared in 1997 models, and the wheels were first available in 1999. The dashboard and instrument cluster are from the newer model. The front blinkers on the 1995 Cherokee were attached to the headlights, not on the front fender.
When Chuck carves HELP in the sand with his foot, you can see the high tide mark of the sea weed is below the letters and the sand is obviously soft indicating it is above the high tide mark. However, in the next scene when the tide has come in and washed half the letters away the high tide sea weed mark is up above the letters.
Early on in his ordeal and early in the morning when Chuck sights a light off on the horizon, as he is prepping to paddle out to the ship which he assumes is there, you can see the rising sun in the same direction off to the left of the light. However, as he starts his short ill fated journey towards that ship's light, the sun is behind him.
When Chuck is boarding the airplane after kissing Kelly goodbye, the aircraft's tail fin has no engine mounted to it. This proves that the airplane used in this shot was not an MD-11, which was used as the model for the cockpit scenes later in the movie. MD11s have an engine mounted on the tail fin, three thrust levers between the pilots, and 6 digital cockpit screens.
When Chuck first finds the port-a-potty piece that washes up on shore, the first shot revealing his left thigh does not bear the long scar shown earlier in the movie. Yet afterwards, the scar appears once again on his left thigh.
When Chuck is first trying to make fire, Wilson in the background has a logo visible in the left top corner of the box, but after he cuts his hand, the next scene shows Wilson's box in a slightly different position and without the logo.
Right after Chuck cuts his hand, while he is trying to create fire, the boxed volleyball is sitting on the ground with the black part of the box on the right hand side. When Chuck goes to pick it up to throw it, the black part of the box is now seen on the left hand side.
When Chuck throws the boxed volleyball with his bloodied hand after the failed attempt to create fire, the box is right-side-up; since he bends down to pick it up, this means that the fingertips should be pointing down on the ball. However, when he looks at the ball soon after, the box is upright but the fingertips are pointing upwards.
As the FedEx MD-11 dives toward the ocean, none of the alarms that should go off during a steep dive (i.e. Excessive Sink Rate, GPWS) are going off. All
aircraft operating out of the United States since 1972 have been equipped with such alarm systems to help prevent crashes.
Chuck is wearing Albert's shoes and the toes of the shoes have been cut off so they would fit Chuck. But, there is absolutely no way Chuck could have cut those shoes. At that point on the island he hadn't opened the ice skates up yet, and even if he had they still wouldn't have been sharp enough to cut through the strong leather of the shoes. When Chuck is wearing them and they show a close up of the shoes, it's a very smooth, nice clean even edge were they were cut. It just was not possible for Chuck to have made that cut to alter those shoes.
When the plane is going down, Chuck watches the ocean's surface approach through the pilots' windshield. When the plane strikes the water, he is thrown backward into the cargo area. In reality, he would have been flung forward, into the cockpit, and likely would have died from the impact.
When Kelly relates to Chuck that the Tennessee Titans "nearly won" the Super Bowl but lost because of "one lousy yard" she is referring to SB XXXIV on January 30, 2000 when the game ended with Titan Kevin Dyson being tackled on the one yard line on the last play of the game. However, the final score of the game was 23-16 so even had Dyson scored and the extra point converted the game would've gone into overtime and the outcome would still be in doubt. It was possible that the Titans could've gone for a two-point conversion to win the game, however it's highly unlikely that a coach would take that chance in that scenario. Thus for Kelly's statement to be correct there needed to be several scenarios to play out in the Titans favor.
The plane was obviously having problems and flying through a storm before going down, but Kelly told Chuck that FedEx decided the plane went down due to some unmarked hazardous material in one of the packages.
In the cave, Chuck has made an analemma, which is impossible without a precise watch, which is stated he didn't have. The analemma is a graph of the difference between solar time and civil time, in any case he only had access to a solar time reading.
Chuck plans for his launch by looking at where the Sun is shining on a rock in his cave. The spot of light makes a figure 8 as the year progresses. But the light spot would have to be marked at the same time each day, as it would also move across the rock throughout the day. It is unlikely that it just happened to be that time of day as he looked at his "calendar", and it is unlikely that he knew what time it was since his watch did not work.
When Chuck enters the cockpit, the altimeter selection of the Primary Flight Display should be completely brown because the plane is in a steep drive. It shows a pitch indication of zero, or level flight.
When Chuck was building the raft to leave the island and ran out of plant fiber to make rope, he states that he has searched the entire island and couldn't find any more plants; however, there was a plant right behind him.
The goof items below may give away important plot points.
When Chuck buries Albert Miller, he scratches "1950-1995" on the rock face above the grave. When Chuck examines Miller's wallet, you can see a close-up of Miller's New South Wales, Australia, driver's license, with a birth date in 1949.
The taxi that carries Chuck back to Kelly's home has its "For Hire" light illuminated. Usually on a taxi with a fare on board, this light would not be lit, but the driver simply forgot to turn it off (which happens regularly in the real world).
In Kelly's kitchen, she explains to Chuck that the Titans made the Super Bowl XXXIV and "almost won" but for one yard. In fact, had the Titans scored, the score would have been 23-22 and the likely result would have been an extra point kick that would have tied the game.
The plane that Chuck was on took off from Memphis, and crashed somewhere in the South Pacific. But at the end of the movie, he delivered the FedEx package he didn't open on the island to an address in Texas. While it seems odd that a package bound for Texas would be on an international flight from Memphis, the woman who lived there was actually the sender of the package and Chuck was returning it to her (hence the soundtrack playing Elvis Presley's "Return to Sender" when he's driving there). The same woman had sent a package at the beginning of the movie to her husband in St. Petersburg, Russia, with similar golden wings painted on it.
When Chuck compares his foot to Albert's shoe his toes hang over the top of the shoe. When Chuck puts the shoe on with the toes cut out, the shoe actually fits his foot. The toes being cut out was just a visual effect.