Well, his dad probably had a private plane by now, or at least a helicopter. Probably both, since Sungmin's mother's family would've provided something if he hadn't inherited them with the job.
"An airplane? Of course not," Sungmin said. "I bought a ticket with an airline." Oh, maybe this was one of those things that Locke didn't have in his world - just like Sungmin was pretty sure they didn't have caves that were portals to other universes. "Wait, what do you mean by airship? We have planes here - they're like..."
He looked around for a piece of scratch paper, realized he didn't have a pen handy anyway, and carefully spread his arms out in an imitation of a plane. "They've got wings like this and they run on jet fuel. Most people don't have their own because they make ones big enough for hundreds of people, so they work like buses."