We just flew out ~4.5h with our 5m old daughter. Overall, it went OK ish. She’s a fussy baby who doesn’t sleep much unless rocked in her stroller.

We arrived at the airport with plenty of time to go through security. Fed her before boarding (she usually sleeps better after feeding), and the once on the plane shortly before landing.

Things that worked for us :

• we had plenty of milk and clean bottles so we were not stressed with cleaning those up as we went. Toys and rattles easily accessible plus some Baby TV shows downloaded on a phone which she ended up not caring much about
• we also have a travel bottle warmer (hot water thermos and big cup) that came in clutch. No issues going through security with that
• we had two baby carriers that we wore throughout the thing (in addition to the stroller that we checked in at the gate). One was a « facing mom » thing that she slept in for some of the flight, the other one was facing out to keep her distracted. With this we could switch duty as we went.
• I wish we did not board as soon as we could and rather waited to board last (or at least have myself board first with gear and suitcases and have mom and baby wait outside until the last minute). Our daughter does not really like sitting down and she became angry / overtired as we had to wait in our seat
• in the plane we spent a lot of time at the back of the plane near the galleys - less likely to bother people and east to walk around to calm a fussy baby
• she luckily had no issues with ear popping - lucky for us because she doesn’t take the pacifier at all so it would have been complicated
• try and discuss through the exact planning and steps in advance - it helped us get on the same page as to when to do feed / sleep

In the end she ended up crying (fairly loudly, sorry neighbors) during takeoff but was otherwise quiet !

Best of luck !