So this is a combination of finance in terms of the F-35 weapon system. The 5th gen fighter is the most advanced airplane ever built and that comes with a cost, it is estimated that the program will cost around 1 TRILLION dollars over the life of the program. The lifecycle is typically 40-50 years for a fighter jet so the financial impact is spread out over many years. Many people from the outside looking in only get the sticker shock but do not realize the advantages this plane will bring to our men and women fighting for our freedom! On top of helping to maintain our air superiority a program of this size activities a large amount of people to help produce it. There are currently 45 states, yes 45 that make parts for the airplane. It can safely be compared to what Eisenhower did with the interstate system. The opponents who claim it is a financial lemon should look into the numbers and see what would happen to the economy if the production was stopped. I am not saying that is solely the reason to keep it in production but it's a very good one! There are over 130k jobs directly and indirectly provided by the program it is the largest job generator in the DOD.
Above are just a few reasons why the F-35 is worth the money, you would not want to be a guy on the ground needing aerial support but none was available due to budget concerns.