Copa Airlines flies PTY-EZE and SFO, which are 2 of the longest 737-800/MAX9 routes, so you could probably end up flying it about 8-9 hours.
GOL also used to operate a 7-8 hour flight from Brazil to Punta Cana to Orlando or something like that, and Turkish Airlines also operates quite a few medium hauls from Istanbul to West Africa.
Usually the 737-800 or 900 is great for it in IF, but you might wanna just stick with a lighter load. To my knowledge they don’t normally block seats on those flights and since the range is almost always higher in Infinite Flight, but you could just reduce the amount of passengers + cargo and you’ll be fine
It wasn’t with the -900, but I flew a Norwegian 737-800 from Stewart International all the way to Bergen, Norway. Albeit I was weight restricted because the 737-800 doesn’t have the range to make a transatlantic flight fully loaded.
Across the US is nowhere near long as some of the Turkish flights from Istanbul all the way down to Central, East and West Africa like Kinshasa, Libreville, Dar es Salaam all in the 739…
They’re nearly 7 hours long. I flew them in IF and I absolutely love them
IST-NBO. Around 6h 30min. As @Igor_M has said above, the 739s can operate longer sectors such as the one I’ve mentioned. Dar Es Salaam is an extra hour of flying past NBO.