Need help quick! Will Triumph fit on airplane seat?

[samiam]

We're headed to Disney tomorrow with ds. I don't want to take his Roundabout out of my car as the police installed it and it's rock solid. I have an Evenflo Triumph (not installed) that I hate. Figured I'd travel with this one and put up with it for a few days vs. taking the Roundabout. I just realized it's big - will it fit on an airplane seat? I've never travelled with my son before and am clueless. We're flying Southwest if that's any help.

I think I've seen people say the Roundabout will fit. Am I right?

Thanks!

[samiam]

Okay, I searched through some old posts. Looks like it might fit but will be really heavy to lug through the airport. Now trying to figure out whether to take my rock solid installed RA out of the car or pick up a Cosco Scenera from Walmart (assuming I can locate one tonight!)

Yikes - wish I'd thought of this sooner!