I just returned from a week in Mexico. It was 4+ hrs going and about 3.5 on the way home. We checked in very early but we were still sat separately so going I was a 1 woman show.
It worked out that it was nap time at takeoff. He slept for that part and for almost 2 hours. I wanted to have him drink his bottle at takeoff but the poor guy was so hungry I couldn’t hold it off any longer. I brought different toys and continued to give him new things once he woke up. He chewed on a bagel for a while, jumped on my lap, looked at strangers, etc. He slept for the landing too. Coming home was actually worse. He was more fussy but I had DH. He ate cheerios, played, stood on my lap and looked around, we sang songs, etc.
Luckily, it seems like his ears were not an issue. He tugged at them a few times but he didn’t cry. I brought a tote type bag and kept it open in between my feet for easy reach. I wiped down everything as soon as we sat. I wore him for boarding and brought the stroller too. They had a special line at Newark for families or others with special liquids and they didn’t even check my bags. On the way home they did and just confirmed my items were for the baby.
It was really not bad at all but since your flight is short and you have a cuddler (mine isn’t) you’ll probably be fine.