The Associated Press

FILE – In this Feb. 12, 2009, file photo smoke rises from a burning Continental Express commuter plane after it crashed into a home in suburban Buffalo, killing 50 people. Federal regulators haven't lived up to promises made after the crash to see that major airlines ensure the smaller airlines who operate flights under contract for them meet the same safety standards, according to a report by the Transportation Department's Office of Inspector General. (AP Photo/David Duprey, File)

By JOAN LOWY Associated Press

WASHINGTON (AP) — Since a deadly airline crash in 2009, the government hasn’t kept its promise to ensure that major airlines are holding their smaller partners to the same safety standards, a federal watchdog says.

The Transportation Department’s inspector general faults the Federal Aviation Administration for not taking steps to encourage the big airlines ‘‘to consistently share safety information and best practices’’ with regional airlines that operate flights under contract for them.

That business link is known as code-sharing, by which one airline sells tickets for seats on a flight operated by another airline — United and United Express, for example.

More than half of all airline flights in the U.S. are operated by regional airlines using names such as United Express, Delta Connection, American Connection and US Airways Express under code-sharing arrangements.