Not sure about your options, but for what it's worth, I flew into Gatwick with two cats and had to make a six-hour drive up to near Newcastle. I was more worried about the drive than the flight, as my cats were extremely vocal about their hatred of cars while in the US; turns out they were absolute angels on the drive up north! I think they were so relieved to see us again after the flight experience that they decided to be on their very best behavior in case we decided to send them back to the US!
In the end, it wasn't anything like I was afraid of (six hours of constant yowling peppered with occasional puking from the smaller one) - Toby curled up in the back window, Xander in my lap up front and there they remained for the vast majority of the journey, silent as mice. So if it's the drive you're fearing....