Traveling with kitty, how do I deal with lack of litterbox?

- Moving guys will collect all my stuff at 11:30 AM, I have to turn in my key by noon and I'm supposed to vacate by then but I know they won't check that day, so I could hang around for a couple more hours but I wouldn't be able to leave without being locked out

- Flight leaves at 5, arrives at 6:30

- ~40 minute commute from airport

7 hours seems too long for him to not have a litterbox, and I really don't want to deal with him going in his carrier. Even if I waited until 2:00 to vacate, I can't predict if he'll actually use the litterbox in that time. The airport has a pet relief station where I can feed him and give him water, but it's designed for dogs and is just astroturf. I'm not sure if he'd know to use it.

For people with experience with long-ish travels/airports:

1. If he has to go, will he use the astroturf?

2. If the answer is no, what am I supposed to do? I know I'm not the first person in this situation, but it seems impractical to just lug around a litterbox and bag of litter.

FYI he's harness trained so I could maybe take him out like a dog? But when I take him out he usually is a little skittish at first until he warms up to the place, IDK if he'll go outside.