WASHINGTON (Reuters) -U.S. Transportation Secretary Pete Buttigieg on Thursday urged the nation's largest passenger airlines to improve travel benefits for active-duty military personnel and their families.

The department in May plans to begin posting comparative information on travel benefits that airlines guarantee for service members and their families on a customer service dashboard.

USDOT plans to detail airlines that will commit to full refunds to service members and their families who cancel travel plans due to military directives as well as allowances for free baggage.

Most carriers give military personnel additional free bags and other benefits like priority boarding or discounted fares. There are about 1.3 million active-duty U.S. military personnel and around 800,000 reservists.

Buttigieg said "benefits are not consistently detailed in carriers' public-facing Customer Service Plans, resulting in many service members being unaware of them" and added that "airlines' travel benefits often do not fully address the needs of service members who may need to cancel or change personal travel plans due to military directives."

Major carriers including American Airlines, Delta Air Lines and United Airlines referred questions to trade group Airlines for America, which praised military members and said "carriers are proud to offer a variety of travel benefits and are transparent about these benefits on their websites."

Southwest Airlines said it is "committed to making the military travel experience as easy as possible" and offers a number of benefits.

The Transportation Department previously posted a government dashboard highlighting airline commitments to not charge families to sit together. In September 2022, nearly all major airlines agreed to guarantee passengers meals and overnight stays for lengthy delays within their control after USDOT first announced a dashboard comparing customer protections.

In May 2023, President Joe Biden said USDOT is writing new rules seeking to require airlines to compensate passengers with cash for significant flight delays or cancellations when the carriers are responsible.

USDOT has not released a formal proposal or specified how much cash it aims to require airlines to pay passengers for significant delays. But it asked carriers in 2022 whether they would agree to pay at least $100 for delays of at least three hours caused by airlines.