The designer of the Kalashnikov rifle was to be airlifted from his home region in central Russia to Moscow on Sunday after falling ill with a lung problem, Russian officials said.
Mikhail Kalashnikov, 93, is suffering from a thrombosis of the pulmonary artery estimated to be of medium severity, news agencies quoted the Russian health ministry as saying.
A plane belonging to the Russian emergencies ministry landed in Kalashnikov's home city of Izhevsk -- where he invented the rifle -- to take him to Moscow for a check-up.
"The doctors have decided to send Mikhail Kalashnikov to one of the Moscow clinics," said emergencies ministry spokeswoman Irina Rossius, quoted by ITAR-TASS.
The plane is already equipped with medical facilities which doctors can use to examine Kalashnikov while airborne. Kalashnikov was already hospitalised for two weeks in May this year.