Why is it cheaper to fly round trip?

Related questions

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4. What is the lowest altitude a plane can fly?
5. Is my flight Cancelled?
6. Will flights get Cancelled?
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9. What days are flights the cheapest to book?
10. Why are most international flights at night?

Tags

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2. #almost
3. #expensive
4. #solid
5. #round
6. #pricing
7. #airlines
8. #relatively
9. #wisdom
10. #after
11. #airfare
12. #seems
13. #reasons
14. #flights
15. #getting
16. #price
17. #always
18. #ticket
19. #conventional