I have this headcanon that, before they part, he always slips a note into her pocket/bag/suitcase. Sometimes she’ll find them during the flight, or later at home when she’s unpacked. But they’re always sweet. Quotes or lyrics, or even just a simple « I love you–see you again soon ». He just seems like such a sweet, romantic kinda guy, & I wouldn’t put it past him to do things like this. <3