Overall good experiences here, flew when dd about 10 mths and again at 18 mths.
One journey I got hemmed into my window seat with her by a man with a broken leg, decided to do a sneaky nappy change on my lap before take off. Naturally she did a massive wee on my lap and I had to sit in soggy trousers throughout the flight and a few hours the other end.
Easyjet kept us waiting SEVEN HOURS last time we came home - and the staff were quite rude. Luckily dd thought it was excellent fun and wanted to charge around the airport shouting hello at people (not sure if they liked that but hey). Take extra snacks/formula if you use it just in case, especially if it's a smallish airport with limited selection in the shops or shops close after a certain time.
One thing I would do is leave a spare day to recover/get your bearings when you get home before going back to work, childcare etc. That way if it is a hairy experience you have time to settle back into things, rushing can lead to dc being unsettled, sleep going wonky etc.
I'd also take a little bag of small new toys to keep in reserve for unexpected delays, grumpy spells etc. I get little dinosaurs and dolls and that for 10p each from a charity shop so I don't care if they get lost.
It's also worth thinking through your transport at the other end fairly carefully - if you're taking a car seat will it fit hire car, or will the taxi have one, that sort of thing. We turned up in one place and the taxi company dug out this car seat that looked like it was for a doll then wanted to just rest it on the back seat without strapping it in or anything... The driver said he would 'go careful and slow'...
Also double check that there will be a travel cot/high chair etc in your accommodation, we turned up somewhere at 11pm to be told they'd forgotten and couldn't find them until the morning. We were used to co-sleeping but could have been a bad night otherwise!