• United Airlines said the Federal Aviation Administration has cleared it to add new aircraft and routes.
• The FAA had stepped up its safety review after several high-profile incidents, including one of the carrier's 777s that lost a tire after takeoff.
• The agency's safety review forced the carrier to postpone new routes, including to Faro, Portugal.

United Airlines said the Federal Aviation Administration has cleared it to start adding new aircraft and routes months after the regulator stepped up its scrutiny of the carrier following several safety incidents.

"Today, we got some good news: after a careful review and discussion about the proactive safety steps United has taken to date, our FAA Certificate Management Office has allowed us to begin the process of restarting our certification activities, including new aircraft and routes, and we will continue to coordinate closely with the FAA," United said in a note to employees Wednesday.

United said in March that the FAA had stepped up scrutiny of the airline after a spate of incidents earlier this year. That prevented it from launching new routes, including flights to Faro, Portugal, ahead of the busy summer travel season.

United said that it has more work to do, however.

"We will continue to see an FAA presence in our operation as they review our work processes, manuals and facilities," it said in its employee memo.

United would send requests to the FAA to add aircrafts or new routes, though a spokesperson said it has yet to do so.

The FAA said later Thursday that it has not yet "approved any expansion of United Airlines' routes or fleets." The FAA said its review is "ongoing and safety will determine the timeline for completing it."

A clearance from the FAA would be welcome news as United and other carriers expect a record peak season this year.

Among the safety incidents in recent months, a Japan-bound United Boeing 777 lost a tire shortly after takeoff from San Francisco in February, and a missing panel was discovered on a Boeing 737 after it landed in Oregon in March.

While the planes involved older jets, the incidents come amid heightened scrutiny of the aviation industry after a door plug blew out of a nearly new Boeing 737 Max 9 operated by Alaska Airlines earlier this year, a near catastrophe that has created a fresh crisis for the manufacturer.