The NSA Agent says finger prints on a cargo hold door were discovered. The very next scene is Bethany's instructions which end in using the landing gear wheel well to escape. The landing gear well does not have access to the cargo hold in any capacity.
During the flashback of Bethany's instructions for the stowaway, she directs the man to go down into the cargo hold and then out the landing gear and run. There is no direct access from the Cargo Hold to the landing gear wells for a 737. Additionally, the wheel wells would put the man right in plain sight of the responding services, he would have been caught the moment he emerged.
It is told that Grace got half a million dollar from the insurance company on account of Ben being dead on flight 828. But, the local laws state that when a dead body is not found, the person cannot be presumed dead for 7 years, so such a missing person's wife cannot even get a divorce for 7 years and should not be able to get an insurance claim for 7 years. Someone better verse with legal and insurance rules in America and NY can fill in how it would be there.
An envelope addressed to Grace has a comma between the state abbreviation and the zip code. The comma is supposed to be between the city name and state abbreviation.
It is continually established that the NSA has full surveillance on all the passengers from flight 828. This would include phone calls, text messages, and GPS locations from their devices. Therefore, when Ben, Michaela, and the rest speak freely when on calls and text each other their plans, the NSA would already know everything before they were able to execute it and any plan would be foiled before it was even set in motion.
Ben calls Olive his 15 year old daughter. In previous episodes, it is mentioned Olive and Cal were born in May 2002 and they are in November 2018, so she would be 16, not 15.
It is a character error of higher power or aliens or whatever it comes out to be later in the series. They are supposed to be superior technology or power but their alarm system is quite shabby. The characters first get the message "Set them free" when they are seeing dogs, thus not able to understand that this is intended to set the two girls free. Now She gets alarm to "Save him", when she was nowhere in the vicinity of Thomas so she couldn't understand it is not intended to Save the agent Henderson, but Thomas, though viewers would get that it might be to save Jared as something might be cooking for him. A superior power should have a much clearer and exact system of sounding alarms or sending signals.
Having spent half a million dollar in some 4 years or so is quite an excessive expenditure on account of Ben's wife Grace, no liquid money nor property or jewelry is remaining with them at this point. There life style doesn't seem so lavish as to have been able to spend such a whooping amount of money leaving no trace of it.