My OMG moment is when Rumple discovered he lost his magic. I think he suspected it which is why he went into the bathroom to injure his hand and then try to heal it to see if he did.
I believe when his shawl was removed, he did forget his memory, but when it was put back on, he regained it. However, when he went thru the security scanner, his magic went away, probably a combination of the scanner and the fact he was not wearing the shawl. Since he regained his memory after the shawl was put back on, it had to be the scanner that erased the magic.
I can only surmise that he thought as long as he retained his memory, he would otherwise be as he has always been. It didn’t occur to him that his magic was at risk outside of Storybrooke, so his potion did not include the necessary ingredients to protect his magic once he went outside of the town limits.
I do agree with Gaultheria, why didn’t he shrink it or turn it into a handkerchief that he could have kept in is pocket?
And as others have noted, why did he want to fly instead of driving? Flying between Logan and La Guardia/JFK takes a LOT longer than driving between the two.
Don't grow up. It's a trap.