Adebolajo — who asked to be known in court as Mujahid Abu Hamza — faces charges of murder, attempted murder of two police officers and firearms possession.
His suspected accomplice, Michael Adebowale, 22, made a separate appearance at another London court via video-link later Monday.
Adebowale is also accused of killing Drummer Lee Rigby, as well as possession of a gun.
Both men were shot by police and placed under armed guard in the hospital after the attack on Rigby, an off-duty soldier who was run over by a car and then stabbed repeatedly while walking back to his military barracks in southeast London.
Wearing a white T-shirt and white trousers in court Monday, Adebolajo blew a kiss to a man in the public gallery, and both men then pointed to the sky.
When asked to stand, Adebolajo did so, but asked "May I ask why?" and said he wanted to sit down.
He was kept in custody to appear at court again within two days for a bail hearing.
Police have arrested and questioned several others in connection with the attack.
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