Federal Aviation Administration spokesman Ian Gregor says all four were passengers in the single-engine plane.
He says there are no survivors.
Gregor says a preliminary investigation shows the Piper Cherokee was en route from the North Las Vegas airport to Byron, Calif., when it crashed at about 2:45 p.m. at the 7,000-foot level on Mt. Charleston.
The plane burst into flames after crashing and was destroyed.
The fire ignited a small wildfire near the Echo subdivision of the resort area.
Fire officials say the flames fire are climbed the steep and parched terrain of the Spring Mountain Recreation Area and are within a half-mile of homes.
Bureau of Land Management spokeswoman Kirsten Cannon says nearly 40 homes are threatened by the 12-acre fire.
Authorities have ordered an evacuation of the subdivision. They expect to fully contain the blaze by 6 p.m. Sunday.
Authorities did not immediately released information about the passengers.