We did a 3 hour trip to Cairns last year when Glenn was just 1yr old & Evan just 3yr old. The flight there was awlful! It was a really late flight & my oh my were they tired & cranky! Mostly Evan. He was bord out of his brains & they stuck us right at the back. There reasoning for sitting us at the back was that it was closest to the baby change table. BUT we couldn't recline our seats one little bit as the seats were against the wall & I had no storage space above my seat as that spot was used for Airline staff stuff, so all of my needed items were a few seats down. When ever I needed something I had to get up. We constantly had people standing near us waiting to use the toilet. Glenn was still BF at the time & it was very difficult to keep him focused on his feed with people standing right there. I felt like I was constantly being looked at. Not that I cared about BFing in public but it has hard to keep Glenn on the boob. Once he did finnally fall asleep ( about 15 minutes before we landed!!) I was so uncomfortable because I was trying to keep him comfy but couldn't recline back what so ever. Evan did walk up & down the aisle a few times but everyone thought he was just the cutest thing so that was ok.
The flight back was a bit better, Other then being stuck right up the back again, the boys were easier to keep amused as in was an early monring flight so they were not as tired/cranky & could see out the window etc.
My only advise is DON'T DO LONG FLIGHTS ON JETSTAR/VIRGIN ETC if you can pay extra for a bigger plane!