Hi K.,
As a flight attendant and mother I do have some suggestions, thought keep in mind I've never taken MY son on long flights. If you've ever taken your child on long car trips you can incorporate some things you've used and done there. The good news is, though your son is crawling, he isn't walking and this means less activity than a toddler. Good for you for requesting the bulkhead seat and a bassinet (though we always recommend purchasing a seat for your child and using an FAA approved child restraint system/car seat). Be prepared though for the airline to make mistakes or to have a change in aircraft model, which could affect your seat assignments, and take it in stride, your child will absorb and react to your behavior and stress. If you can, look into requesting an infant meal, you can always take with you what he doesn't eat. Either in your diaper bag or another tote/backpack, bring NEW surprise books and small toys to keep him interested and occupied. Don't let him see the contents until the moment you need them and only one at a time. Try not to introduce more than one an hour and you can always bring old favorites as well. TSA does allow parents to bring formula or pumped breast milk, but I recommend powder for those who use it for ease of travel. Check out TSA.org or your airline's web site for family travel suggestions.
Try to only be out of your seat while the seatbelt sign is off, and be prepared for unexpected turbulence. I have seen parents hurt during flight and unable to care for their kids, so never put yourself at risk, even if you can't stand the smell of that diaper.
Lastly, and only from the mind of a flight attendant, keep in mind the crew is there for your safety. There are certain things they can and can't do or can and can't allow. Please never hand them trash during any food or beverage service (and never hand them dirty diapers), their hand are clean for the service. Though our airline asks us to never hold a child unless necessary, I have many times (I can't help myself, I love children). We are instructed to recommend warming a bottle or food jar against the parent's body to prevent over-heating and burns, but ask for bottled water to mix formula of you can, I don't suggest using tap water for anyone under 1 year or with suppressed immune systems. We do not have microwaves on airplanes.
I could go on but I've bored you long enough. Safe travels and feel free to contact me if you have specific questions.
S.