Dear parents, how early do u plan for an overseas trip (taking flight) with your baby?

Just did a short getaway with my #14week LO. The flight time was short but I guess choosing the flight time which is close to his sleeping or nap time really helps. LO slept through the flight departing, didn't even wake up during turbulence. I let him suckle before plane take off and he drifted off to sleep really quickly. Did the same for the return flight.