Most people arrive undecided if flying the Nazca lines. Definitely we recommend the experience, the best tip we can give you is try to be relaxed, dont get the nervous get to you.
Try to learn as much as you can beforehand about the Nazca lines, we provide our passengers with lots of information about the flight circuit, and the time approximately you will arrive at them. Our first tip is to avoid to see trough your neighbor window, focus just on your own window.
Another recommendation is to arrive a day earlier in Nazca, we usually provide our passengers with a lecture about the Nazca Lines at the planetarium. Is important to know that if you arrive directly at the airport most likely is that the people at the counters wont care if you have information about the Nazca lines, their mission is just to sell you a flight ticket and get you on the plane.
Another important advise is to visit them by land, we assure you you will enjoy this land tour, regardless if you fly or not. The 3 hours visit to the Palpa and Nazca loo-outs defenitely will give another perspective of the Nazca Lines, you will able to see how they were made, and how they look drawn on the desert floor.