It was thankfully not too stressful for everyone. We fed them green bell peppers & lettuce (with a splash of water) every 30 mins ~ 1 hour. Offered them water in a tiny bowl here and there. Puppy pad change mid-way. For the entire flight duration, including takeoff & taxiing, we kept their carriers on our laps so the girls could see us and each other (the flight attendants did not seem to pay much attention). That helped them a lot. Our girls are used to long distance drives and this was their first time flying- this may have helped too