| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Flights-What-is-the-Cheapest-Day-to-Fly-with-Southwest-Airlines.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Flights-What-is-the-cheapest-day-to-book-a-flight-on-Copa.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Smart-Booking-What-is-the-cheapest-day-to-book-a-flight-on-Copa.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Low-Fare-What-is-the-cheapest-day-to-book-a-flight-on-Copa.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Low-Fare-What-is-the-cheapest-day-to-fly-Spirit-Airlines.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Deals-What-is-the-cheapest-day-to-fly-Spirit-Airlines.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Flights-What-is-the-cheapest-day-to-fly-Spirit-Airlines.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Flights-What-is-the-cheapest-day-to-fly-with-United.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Cheap-Deals-What-is-the-cheapest-day-to-fly-with-United.pdf |
| https://amtrakoig.gov/sites/default/files/webform/foia_form/_sid_/Smart-Booking-What-is-the-cheapest-day-to-fly-with-United.pdf |
