Defense Travel Simplification Act of 2007 - Requires the Secretary of Defense to: (1) redesignate the Defense Travel System as the Defense Travel Accounting and Voucher Processing System; and (2) establish an intra-agency task force to recommend measures to streamline and simplify the commercial travel system used by the Department of Defense (DOD) through the establishment of a successor system to replace the Defense Travel Accounting and Voucher Processing System.
Requires the successor system to include an Internet-based travel system designed to identify modes of travel, hotels or other accommodations, or rental vehicles. Prohibits any successor system from being deployed until 90 days after successful operational testing by the Secretary.