About fifteen minutes later, he hadn't returned. This Houlihan's also has an upper level and we thought it might be plausible that he had tables up there too, so we waited another few minutes. The only two registers on the lower level were within our view, and we hadn't seen him around there since he'd taken the check. Finally, at 6:25, one of my coworkers went to ask somebody where we might find our server, since he'd picked up the check 25 minutes ago. Her response: "I have no idea. Don't worry, he isn't going to steal your credit cards!" It hadn't even crossed any of our minds that he was going to steal their cards - we were just worried about getting through security and making our flights. Another ten minutes went by, and he still hadn't returned or shown up anywhere we could see him. In the meantime, my coworker ran upstairs and did a sweep of the entire upper level and didn't see him there, either.
Finally, at 6:40 or so, he returned with the check, casually dropped it on the table, and said "When you split checks, you have to get a manager to approve it," and walked off. Okay, I'll buy that, even though I've never run across that before (working or dining). Regardless, I don't know how getting a manager approval takes 40 minutes, especially in an airport restaurant (where people are generally in more of a hurry and less likely to have time to linger over food or drinks). Anyway, we figured we'd just hope for the best at security and get through in the ten minutes we still had before boarding started. Right?
Wrong! My coworkers opened the book to sign the receipts and lo and behold, it was the wrong check and the server had returned someone else's credit card to us, meaning that their two credit cards were probably at someone else's table. So we found the server (who, mercifully, was still in sight this time) and showed him the mistake. He casually grabbed the incorrect check and started to walk away without another word, before one of my coworkers called after him that we were really in a hurry. After another ten minutes, he returned with the correct check, which he dropped on the table before wandering away without another word or any explanation or apology for the delay or the mixup. At this point, it was 6:55 and we had 25 minutes until our plane took off, we hadn't even gone through security yet, and my coworkers (who handled themselves well through all of this despite being douchey corporate types) were fuming.
In the end, something magical happened - we made our flight due to this very surreal TSA agent who appeared out of nowhere as we approached the security line and guided us down a long glass corridor to a completely vacant security area where each of us got our own empty security checkpoint to go through, and the agents were all singing some weird song about Burger King and having it your way that they'd made up. Honestly, that part kind of made the whole thing worth it.
Tl;dr - Go to grab a quick bite at airport Houlihan's, server mysteriously disappears after taking our check and doesn't come back for 55 minutes, we almost miss our flight but don't thanks to great service from TSA (I KNOW!).