My 22 month old daughter has now been on over thirty five flights with me. On at least a dozen of them, I had her by myself. What has been one of my best baby purchases is GoGo Babyz-travel mate. It is a set of wheels that attach to most convertible car seats (it works great with our Britax Decathalon). The wheels are good quality and can take a beating. The handle is long, sturdy, and retractable. I even attach my carry on to the handle to reduce my load. My daughter likes it so much, that 90 per cent of the time we don't need to take a stroller, because, she prefers to ride in her "special chair". Because of this, I did track down a sun shade canopy that attaches easily to her car seat, because that was the only real problem with using the car seat as a full time stroller, while traveling.
SECURITY: There are family lines at most every airport, which are prepared for testing any liquids you bring on for your son. As you probably know you are now allowed to take milk, juice, water, etc. for a little one. Anyway, if yours has one, use it, as other passengers can choose a different lane, if they don't have patience. As someone else advised, be prepared; have your liquids easily accessible, try to put things through the machine in the order that you need them on the other side. Take it one thing at a time. I leave my daughter strapped in until every thing else is done (including the mandatory removal of HER shoes). With the GoGo Babyz wheels attached, often the car seat won't fit through the machine. No big deal, TSA just hand inspects it and it's usually returned to me shortly after we walk through.
BOARDING: I have thus far, always gate checked the car seat (with a bag to protect it), and that was my biggest challenge: trying to wrangle it into the bag (after wheeling her down the jetway in it), while keeping her from wandering. You wouldn't have that issue since the car seat goes on with you. However, the width of your car seat vs. the narrowness of the aisle could prevent you from wheeling all the way to your seat. Can you carry the seat with son in it? If not, I'm sure someone (flight attendant, gate agent, fellow parent passenger) would help carry the seat while you carry your son.
If you decide the GoGo Babyz won't work for you, another convenient option is a car seat back pack carrier. Carrying whatever you can on your back is always a good tip when traveling with baby. And if your husband or someone is available to accompany you to the gate, the escort pass is a great idea. In our travels, that has not been an option the majority of the time.
Best of luck, and happy travels. :-)