JFK - KWI just a few years ago. My girlfriend and I booked a quick 4 day trip there and back after seeing a random flight deal with Kuwait Air, I think it was like $300 rt or even less. We were on their 777 which was actually very nice and there were a total of 7 other passengers on the outgoing segment. It made it a really fun ride and the crew had a great time with it. It was fascinating to learn their backstories. There was only one Kuwaiti, the rest came from Montenegro, Serbia, Bulgaria, a few other Euros, and the Philippines. The return to JFK was not much more full - I believe something like 40 passengers total, which feels like you have your own private jumbo jet.

BOS to MKE on Midwest Airlines 717, departure after 10 PM, I was one of 2 people, the FA got on the horn and said, "You can have all the cookies you want, and sit wherever"

A domestic flight at the beginning of COVID. It was me and just a few other passengers (<10).