My best airline food was on a flight from Papeete to Sydney on Air Tahiti Nui. This was quite a few years back, but it was superb for "cattle class".
My best meals sponsored by an airline was British Airways when the entire airline came to a halt due to a catering strike. I had just flown into London from Atlanta with no food on the plane and then was stuck in Heathrow, together with a few hundred thousand passengers from around the world. I and my delivery crew were each given a £10 food voucher by the BA enquiry desk. I looked at it and told the woman behind the desk that you could not even get a plate of fries for £10 in the airport restaurants, never mind a burger! She looked at me and my bleary eyed crew, asked where we had arrived from and when told, gave us a whole book of 50 £10 vouches and told us to enjoy ourselves. We did and nearly missed being allocated a hotel for the next week whilst the strike continued!
My worst airline meal was on our national carrier, SAA, on a flight from JFK to Johannesburg. Only after takeoff were the passengers informed that there was no food or drinks other than water for the flight, due to a catering strike, but that the airline crew had managed to obtaine tins of tuna and packets of biscuits for "snacks". It is around a 14 hour flight! There was just one problem. Due to US Homeland Security restrictions, no metal "sharps" were allowed on the aircraft and thus there was no means of opening the few hundred tuna cans! That was my last flight supporting our national carrier.