Numerous whistleblowers say the U.S. Federal Aviation Administration (FAA) allowed lapses in crucial aircraft inspections.

The House Transportation Committee hearing was triggered by whistle-blower complaints about Southwest in which the FAA later said the carrier knowingly flew more than 40 Boeing 737s that had not been inspected.

In the last week, United, Delta and American have all temporarily taken planes out of service to comply with an FAA-ordered audit of all airline maintenance records.