Flight time choice

Looking at booking a trip with a will be 17-month old, 4 hour flight. If you had a choice would you choose to fly at nap time or early morning? If she naps amazing, but worried she won’t and then we’re entertaining a tired toddler!
Bear in mind that we are still on two naps at this stage, so not entirely sure when we will drop a nap and what time it will fall exactly, but assuming around lunch time. Flight prices very similar for both options.