By David Shepardson

WASHINGTON (Reuters) -United Airlines can take delivery of new airplanes as U.S. aviation regulators review the carrier, the head of the Federal Aviation Administration said Thursday.

“We are permitting them to take deliveries of aircraft. Most of those aircraft have been one-on-one replacements for missing aircraft,” FAA Administrator Mike Whitaker told reporters at a briefing. “Some of it has been growth. They have provided us with their growth plan, and we’re working with them on that growth plan going forward.”

United did not immediately comment.

Some United certification activities were halted after the FAA said in March it was increasing its oversight of United following recent safety incidents.

The FAA said earlier this month it is requiring the presence of FAA personnel when United conducts final inspections of new aircraft replacing older models.

The FAA said this month the review, known as the Certificate Holder Evaluation Program, “is ongoing and safety will determine the timeline for completing it.”

The evaluation is to ensure the Chicago-based airline “is complying with safety regulations; identifying hazards and mitigating risk; and effectively managing safety,” the FAA said.

United, in a May 16 email to its employees, said the FAA was allowing the company to begin the certification process restart “after a careful review and discussion about the proactive safety steps United has taken to date.”

The airline delayed the start of two new international routes last month, citing a pause on some certifications by the FAA.

The FAA’s Certificate Management Office for United had raised concerns about a series of safety incidents, officials said.

(Reporting by David Shepardson; editing by Jonathan Oatis and Diane Craft)