Character mistake: When the plane is speeding down the runway at the beginning, a female flight attendant is seen walking, and Kyle is seen buckling her seat belt. Everyone would have been sitting down and buckled in at this point.
Character mistake: An air marshal would not give such leeway to someone detained for such disruption. The person would be detained and immediately routed to the nearest airport for investigation or arrest.
Chosen answer: He didn't know for sure, but he had a hunch. As far as he could tell she would arrive early to register the body for the U.S. and they would let her board the plane first (as a common courtesy, since her husband died) Plus, he knew that she had knowledge of planes and that it was her interest to see a new model of an aircraft that she helped build before it was to take off.
Jason Riley