Delta Air Lines Inc. (DAL.N) pushed back the U.S. debut of Airbus SE’s newest aircraft by a week because it can’t get needed approvals for the flights from the Federal Aviation Administration during the government shutdown.

Inaugural flights of the Airbus A220 will be reset to Feb. 7 from Jan. 31, Morgan Durrant, a Delta spokesman, said Friday. Other aircraft will be substituted on the routes so no flights will be canceled and customers won’t be affected, he said. The changes will show up in Delta schedules Saturday.

Delta plans to use the A220 to replace older, less fuel-efficient aircraft in its domestic fleet. It needs FAA workers to conduct inspections, issue certifications and complete test flights before it can make commercial flights with the passenger jet, which has never been flown by a U.S. carrier.

The airline has four A220s now, and the initial flights are scheduled to connect New York’s LaGuardia Airport with Dallas-Fort Worth and with Boston.

Delta’s original order for 75 A220s was placed in April 2016, throwing a lifeline to the plane formerly known as the Bombardier Inc. (BBDb.TO) CSeries. The Canadian manufacturer ceded control of the struggling aircraft program to Airbus last year. Delta added 15 more orders earlier this month.