Air Force One took off from McCarran International Airport about 7:15 p.m. Wednesday following Obama's eighth appearance this year in Nevada.
Obama spoke before a Democratic campaign audience of more than 8,000 people at a convention hall just north of downtown Las Vegas.
Obama's visit comes after Republican presidential candidate Mitt Romney addressed a National Guard Association convention on Tuesday in Reno.
Both candidates are wooing voters in a presidential battleground state with six electoral votes at stake Nov. 6.
Obama won Nevada in 2008 over the GOP candidate, Arizona U.S. Sen. John McCain.