This is our first airplane trip as a family of 4. So far we have done everything as road trips which means we are free to just stuff as much as we'd like in the back of our minivan. This time that won't be the case, so I'm curious as to how many pieces those of you fly bring with you? What do you check, what do you carry on? What type of luggage do you use? I'm also trying to decide if we need to get some real luggage, so far we've just been using random bags that we've accumulated over the years. Thanks!