probably not the best idea on a moving and sometimes shaking vehicle...especially if your airline is decent and provides a complete tray of food...

would it be easier to stand up, drop the table and then sit down again?

have you ever asked the fa if you can eat your meal elsewhere on the plane? maybe theyll loan you a biz class seat for your meal... you may have a chance if you are flying an airline like singapore or emirates...

my next idea is to try and get a large tupperware container like one that is around the size and shape of a lasagna pan or the larger cube ones... you can transfer the containers for the courses of your meal into it either side by side or stacked if you have a cube style container....that way you can angle your tray a bit and nothing will slide off while you hold the smaller course container (dessert, entree, salad....etc) that you are currently eating...portable table things might not work well...

basically, use the tupperware like a tray with higher walls on the side. that way you can rest it on your knees safely while handling the course that you are eating... if you have a meal option, take the ones that are easy to eat with just a fork....rice n curry, pasta, paella. stick to wine if they have it in little bottles...or bring an empty sporting bottle...one with a wide easy to fill mouth, fas wont refuse if its easy to fill, just take off the cover/straw thing and pass the main part over...then you can stash it in your seat pocket or hold between your knees...

cup-straws work well if you can find any color besides these http://image.orientaltrading.com/otcimg/26_2066.jpg