In addition, COA Circular 2023-004 dated June 14, 2023 re: Amended Documentary Requirements for Common Government Transactions, under Traveling Expenses, one of the requirements is:
Quotation of plane fare for similar dates, from at least three airline companies/travel agencies or its equivalent. In case of less than three quotations, a certification by the claimant attesting to such
circumstance, signed by his/her supervisor.