I have three laptops with me every time I fly. They go in a roller-style briefcase that fits under the seat on every mainline aircraft type I've ever flown in on United (50,000+ miles last year and 38,000+ so far this year). On UX it fits in the overheads. Mostly fly US domestic but also one r/t each year to Canada and Australia, never a problem in any location.

I'm quicker getting the three laptops in their separate bins and all queued up ready to xray than most people are just taking off their darn shoes. Only thing I ever get from TSA is wisecracks about how busy I must be or something along those lines. I do everything quickly and efficiently and I can't remember the last time I had a secondary or even an ETD swab.