Demetruis Glenn and Kenan Adams-Kinard are being tried as adults in the case that has sparked nationwide outrage.
The teens said little during their separate appearances before Spokane County Superior Court Judge James Triplet.
They are accused of beating Delbert "Shorty" Belton to death in his car outside an Eagles Lodge on Aug. 22.
A letter found at the home where Adams-Kinard was arrested said they punched Belton three times before taking his wallet and drugs from his pockets, authorities said.
Belton's body was found wedged between the front bucket seats, with his lower body folded into the back seat. The suspects' fingerprints were found on the doors of the car, court documents state.
The teens were being held on charges of first-degree murder, first-degree robbery and conspiracy to commit first-degree robbery. They could face life in prison if convicted.
The letter indicated Adams-Kinard had called Belton and arranged to buy crack cocaine. However, police have said there was no evidence that Belton was a drug dealer.
"The kid wrote a letter to his mom admitting this crap and now he pleads not guilty," Ted Denison, a close friend of Belton, complained after the court appearance. "That's bull."
Belton was born in Sunnyside and raised in Spokane. He got his nickname as an adult for being just over 5 feet tall.
After the war, he spent 33 years working for Kaiser Aluminum before retiring in 1982. He survived being shot in the leg in the battle for Okinawa.
Glenn, who turned himself in, was being held in lieu of $2 million bail, and his trial was set for Nov. 9. Adams-Kinard, who is suspected of hiding from police after the slaying, is jailed on $3 million bail. His trial is set for Nov. 4.
The Associated Press does not generally identify minors accused of a crime but is naming the teens because of the severity of the charges.