Both companies will compete for task orders under the potential 15-year contract, which contains three four-year options, GSA said Friday.
Task orders encompass travel planning, authorization, reservations, ticketing fulfillment, expense reimbursement and travel management reporting functions.
More 90 agencies book travel and track their approvals, spending and vouchers by using ETS.
GSA says the cloud-based e-booking service saves the federal government nearly $20 million a year.