Why are same day flights so expensive?

Related questions

1. Can you cancel flights and get a refund?
2. When's the best time to book a flight?
3. Can I change my Aer Lingus flight?
4. Do airline prices go down last minute?
5. Can I change my return flight date?
6. Do flights ever get cheaper last minute?
7. What is a hacker fare?
8. Can I change my return flight date Qatar Airways?
9. Does Easemytrip charge convenience fee?
10. What happens if I don't show up for a flight?

Tags

1. #prices
2. #called
3. #fares
4. #advance
5. #higher
6. #carriers
7. #sectors
8. #certain
9. #promotional
10. #expensive
11. #always
12. #while
13. #flights
14. #particularly
15. #simply
16. #flying
17. #domestic
18. #another