Yes - I'm assuming Larry is probably under 10 lbs, right? (Most airlines have an even bigger limit, either 15 lbs or even just big enough to fit in a certain sized crate or travel bag.)
I would definitely do it, depending on how long the flight is. A 6+ hour one I might be wary of, but a 3ish hour flight I'd definitely do.
You should just call whatever airline you're thinking of flying on and ask them about their policy regarding pets. Some require an extra fee, I don't know if any allow small pets for no fee. He'll need to stay in the bag under your seat, but usually if your neighbors are okay with it the flight attendants won't mind if you take him out to hold him for a bit once the plane reaches altitude (just ask first).
I have seen airlines kick people off if their dogs were really obnoxiously, incessantly barking...so if you think he might do that, you may want to look into some kind of sedation/meds - valium or even just benedryl - but try out a dose at home first.