Try to fly Southwest until he's 2. That way if the flight isn't full no one will choose to sit by you and you can have a seat for him. When you have to start buying a seat for him sometimes I find it best to purchase from the other airlines since they assign your seat and tr to be one of the last ones to board so he doesn't have to sit still as long. Since you are assigned a seat it doesn't really matter if you get on towards the end. When he's in the infant carrier the turbulance should knock him right out, especially if he's sucking on bottle. Take lots of extra formula in case of delays. We sat at Sky Harbor on Thanksgiving Day for about 6 extra hours and I would have run out of formula if I hadn't bought the pre-maid, ready to go Similac 8 oz. bottles. Soooo handy. Just attach a nipple and you can dispose of the bottle when he's done and you don't have to worry about having so many extra clean bottles with you.

Also, I would recommend taking a little stash of "Wet-Ones" or something to disinfect the trays, arm rests, seatbelts. You never know if the person before you had the flu. It REALLY SUCKS when babies wake up with a fever while on vacation. (Always have Tylenol and Motrin with you in case he spikes a fever. My daughter had a febrile seizure when she was just over 1yr. She spiked a quick fever while coming down with croup on a trip to Denver.) Anyway, when he's older he will probably want to touch everything around him so I think it's nice to take the extra precaution. That way if he does get sick, at least you'll know you did everything you could to prevent it. Good luck and don't stress out about the people around you feeling annoyed by a baby. (Sometimes I take something right before to help me relax because it will be a very stressfull day. Security alone is a nightmare with a baby. You have to take him out of the carrier, put it and the stroller through the x-ray and make sure you take all of your liquids out of your diaper bag. I'm out of town right now so it's all still very fresh in my mind. It sucks.)

I've flown alot with my oldest daughter and would say to plan the trip around your baby's nap time and make sure to not let your little one sleep until after you are on the plane.  You should also plan on nusring or give your little one a bottle during take off and landing.  It helps with their ears popping.  I would also advise you to put an extra shirt for you in the diapper bag as a carry on.  On one flight my daughter had gotten sick all over me and I didn't have anything to change into.  From that time forward I made sure I had plenty of rags in the diaper bag, along with a shirt for me.  We also try and sit in the middle to back of the plane since more families tend to be located there and the last thing 1st class people want to hear is an upset kid. 

What I had started doing with my daughter  when she had gotten older was right before the trip I bought a bunch of little, cheap toys that she hadn't seen before and put them in a back pack along with her favorite snacks.  So when I thought she was about to get restless, I would bust out with a new toy and that would keep her busy for awhile.  Because they were cheap, I wasn't upset if she lost one or two of them in the airport/hotel/taxi or whereever. 

Monica, you have gotten a lot of great advice (minus richtig's) for the Vegas trip. What you should consider when flying the whole way to Boston is, as others have pointed out, take the carrier seat with you. The probability that the seat next to you won't be taken is 50/50 for the most part. BUT, many airlines will move your seat to one that has a vacant seat next to it. This way you are not holding him for the whole flight. We love the little rascals, but holding them for a few hours for each flight (and subsequent connecting flight(s) depending) can be real drain.

He is/will still be young enough, even in a month or two or three, to sleep through most of the flight. There is something that seems to come over infants when they fly, maybe altitude, that allows them to sleep through the process, especially if they have something to suck on. Sucking on a pacifier is pretty much the same as us chewing gum to keep our ears from popping!

There is nothing more annoying than a screaming baby on a plane, except for snakes of course.  But babies are a very close second.

And FYI parents, we don't understand and it does bother us.