Complex sentence: A- 10 and F-16 aircraft that flew in combat rarely got shot at and did not employ weapons on most flights, so for mostly just flying it cost tens of thousands of dollars an hour and used up the service life of high-end assets.
Split into simpler sentences: A- 10 and F-16 aircraft that flew in combat rarely were shot at and did not employ weapons on most flights. Resulting costs were in the range of tens of thousands of dollars an hour and used up the service life of high-end assets.