We just completed our first international trip as a family of 4 and I have to say it was successful!
6 years ago Kayla and I flew to Denmark with my mom and sister. Joe was TDY for 6 wks at that time and, obviously, Lucas wasn't even born yet. So Kayla has been overseas with me before but we hadn't taken a trip like this with the 4 of us.
We went, again, to Denmark. I have cousins over there and ever since Kayla and I went over there Joe has been saying he wants to go too. My cousins flew to the states last year for my sister's wedding so this year was 'our turn' to go to Denmark and we finally made it happen.
Denmark is 6 hrs ahead of us and the flight (thankfully we flew direct on SAS) was 8 hrs. We left at 530pm on Fri night and arrived 730am Sat morning. The kids slept for maybe 1 or 2 hrs, but it was restless sleep at that.
Once we got to Denmark we got our rental car (oh, just because the van I reserved said it seats 7 doesn't mean that is 7 passengers WITH luggage. Thank goodness we only needed 6 seats so one of the seats could fold down and fit our luggage!) and then we drove to our family's house for breakfast. The kids, surprisingly, had plenty of energy to jump on the trampoline!
At 230 we headed for our resort and Lucas crashed in the car shortly after that. We could not wake him up AT ALL and finally gave up and tucked him in to bed at 6pm. (Noon back in the states). The kid had been up for about 24 hrs. He slept until 10am the next morning! Kayla kept going and going until we all went to bed that night. I don't know how she was functioning!
We had a wonderful time in Denmark (even though you have to pay for your water at the restaurants and the food is so much more expensive!)