Its not a problem, chill! Honestly! We took a 2y8m and 8m to Italy, a 16m old and 3 year old on a touring holiday in British Columbia/Alberta in a camper van (while I was 5 months pg), and backpacked round Central America with a 17mo, 3yo and 5yo.
I know that it sounds like showing off - but really, it wasn't hard. Good sunscreen, plenty of water, bananas, regular snacks and naps, go slow, wetwipes, plasticine, pens, finger puppets, kiddy tunes on the ipod or similar (with kiddy friendly headphones), remember calpol. Self catering can help - we did that as much as we could.
It does help if your child is flexible. Our kids never had a serious routine, but did have a bedtime routine we could put into place anywhere (had always done it at grandparents houses/friends etc) including getting on the plane - going to Canada we had an overnight flight and just got into jammies before we boarded!
I wouldn't keep him awake all day - overtired toddlers on a plane are likely to be a nightmare!
Something to drink or suck as the plane is taking off is good - we relaxed all our normal rules and brought sucky lollies once they were past the breastfeeding/sippy cup bit - still do.
Travel is great for kids - you will love it! We have carried on travelling with the children, France, all over the UK, and are off to the Carribean in a week .
Hope it goes well!