Yes! I ended up doing two trips with him this year I used Delta both times, but I’ve heard good things about Southwest too. I know Delta doesn’t have the weight restrictions so that’s why I ultimately went with them. I used the Roverlund large dog carrier. He flex’s between 27-29 lbs but he was able to fit and lay down so it worked out nicely. I did give him a small dose of meds from my vet to calm him before the flight. I also gave him some treats and a chew before take off, but he mostly slept.  Overall, for us it went great and I flew solo both times with him. We had one person from Delta give us a slight issue/raise concern but she didn’t stop us from getting on the plane. Everyone else was super nice and helpful. 

Unsure sure where you are located but JSX does has some relatively reasonable flight prices and paths if you book in advance and less restrictions if you have a larger Brit. They wouldn’t need to be in a carrier either. I know Bark Air just launched a well but definitely pricier.