The National Symphony is out of town. But if your Labor Day weekend isn't complete without a concert on the Mall, The Airmen of Note have the answer. The U.S. Air Force's jazz ensemble will be performing Friday at 8 at the Sylvan Theater on the Washington Monument grounds. It's free; if you're taking Metrorail, exit from the Blue or Orange lines at the Smithsonian station. 767-5658.

Two Labor Day music events are also in the works:

* The Arts Connection holds its last outdoor "Music for the Inner City" concert on the grounds of Our Lady of Perpetual Help Church at 5:30 p.m. It's a program of light classics, including works by Bach, Beethoven, Mozart, Strauss and Sousa. There'll also be a dance demonstration by Colette Yglesias, and a solo performance by baritone Gordon Hawkins. Refreshments will be available. Rain date is Tuesday at the same time and place. The church is at 1600 Morris Road SE. Call 699-5440 for directions and information; free.

* There'll be a "Oldies but Goodies" concert in Langdon Park from 4 to 9, featuring some fun-filled bands from the '50s and '60s like Pookie Hudson and the Spaniels, the Jewels, the Veltones and Jimmy "Handy Man" Jones. The park is at 20th and Franklin streets NE. Call 673-7660 for directions and information; free.