Bart Migom was on his way from Brussels to Atlanta on Tuesday to see the woman he called his “Georgia peach” and “partner in Christ.”

Mr. Migom, 21, met his American sweetheart five months ago at a fitness retreat in Georgia. Since then, he and Emily Eisenman, also 21, had been posting selfies and portraits with each other to Instagram and Facebook. He bought her Belgian chocolate for Valentine’s Day, and she declared herself “Googly-eyed.”

“Distance means so little when you care about someone so much,” he wrote on Instagram.

“I couldn’t wish for anything more this Christmas,” Mr. Migom said in another post, adding: “Blessed to the highest degree.”

Ms. Eisenman, a student at the University of North Georgia, said she last heard from her beau on Tuesday, when he was on the train to the Brussels airport. She never got the follow-up text message she expected confirming that he had his boarding pass in hand.