Flying with puppy first the first time - crate advice

[Michele Kiss]

Hi all. Posting in this forum as well as the Puppy one.

We are planning on flying with our 18-week miniature labradoodle (Fenway) in two weeks. He is still small enough to fly IN-cabin under the seat in front of us (I would NEVER trust an airline with my pet in cargo, OMG.) And he may stay small enough, which we're hoping. We want him to be used to all kinds of experiences, like flying, and hope to travel with him many times, so taking him while young is important. 

We have a soft-sided carrier, etc, for the flight itself. I have flown with a cat before so I know the usual drill (don't feed them / give them water X hours before flight, health certificate 10 days before, etc.) I've also already booked him in the hotel, on the airline, and the Airline's rules are under 20lb for in-cabin so he's fine. His carrier will be fine to fit under the seat. Ironically... he is the same weight as my cat and I've flown multiple times with her - LOL. 

My question is about the crate. He is a crate-trained puppy. Should we be taking his crate with us?! Or buying a separate "easy to pack, fold-up style" travel crate? It would definitely have to be checked baggage. (It does fold up, but it's one of the typical wire crates.) And if we don't, where does he sleep? I feel like his carrier is a little small for a whole night's sleep? And it seems dangerous for his first night of NON-crated sleeping to be in a hotel where he could get up to god knows what while we're asleep.... 

There are tons of sites out there for advice on traveling with a pup, but no one ever seems to talk about this specifically. Any advice? 

Also, because we're in a hotel, I'm tempted to put out pee pee pads so he doesn't ruin hotel carpet :-/ But not sure if that will "undo" potty training, which he's been REALLY good about more recently. 

Would love any advice folks might have...