The shots of the plane from outside show a McDonnell Douglas DC-10 but the inside shots are from a much smaller plane. The DC-10 was a 747 competitor with room for up to 380 passengers. Its interior is much more spacious, with two aisles and nine-abreast seating. (The picture in the newspaper clipping shows yet another different plane, possibly a Boeing 717, but that is a common mistake newspapers make.)
At 28:24 Flynn looks at TIBBAR in a mirror, and sees RABBIT. The reflection should show the letters reversed/flipped.
One of the ships lost in the Bermuda Triangle was called the "Tibbar". When Flynn encounters the stern of the ship on the beach he looks into a mirror and realizes the the name is "Rabbit" spelled backward. However, in the mirror the R and the two Bs are not mirror images as the direction of the letters is not reversed.
He's in a magical place, so the letters appearing correctly and not backwards is part of the magic.
After the port side door on the airplane is opened, an exterior shot of the plane shows the door closed.
When squabbling aboard the plane, Cassandra states "The Triangle's window is unpredictable." This is clearly not true within the framework of the story since the very window they are making use of has been predicted by the Library's own clippings book a day in advance.