Obama was scheduled to arrive in rural Roseburg late Friday morning.
Many locals are angry with Obama for calling for tighter gun restrictions in the wake of last week's shootings at Umpqua Community College that killed eight students and a teacher.
About 200 protesters were milling around outside Roseburg airport Friday, some carrying placards saying Obama was not welcome and "Obama Go Home." At least one person was wearing a sidearm.
"By coming here, Obama is going to politicize a tragedy by saying that you have to have gun control," said George Starr as he held a small American flag.
"I'm here to tell Obama he is not welcome in our county. He is exploiting the local tragedy with his gun control agenda," said Bruce Rester, a retired truck driver who was wearing a handgun in a holster over his chest. "Everybody should carry a gun. An armed society is a polite society," he said.
The White House has said Obama will meet privately with families of the victims but is not expected to make any statements about gun control.