K.G.
If you can, try to schedule it for a time when he would normally be taking a nap. That tends to work well because the noise of the plane usually knocks little ones right out.
As far as him having his own seat, unless you are planning on bringing your car seat with you to the gate, I do not think that the flight attendants will allow it. Children need to be in their parents arms unless they are properly restrained in a car seat or other airline-approved system.