It is not clear why they thought the planes would not be shot down if they had succeed in getting them.
A foiled Chechen rebel assault on the Russian city of Nalchik this month was in fact a "grandiose" attempt to replicate the 11 September attacks and hijack five planes that could be flown into targets such as the Kremlin, a nuclear power station and other strategic facilities, it has been claimed.
That alarming hypothesis has been put forward by an authoritative American intelligence provider called Stratfor that boasts of close links to the Russian and American security services.
The information is being checked by Russia's Deputy Prosecutor Nikolai Shepel, who is investigating the attack on 13 October that left at least 120 people dead and took thousands of special forces to repel.
It was the most significant Chechen rebel attack since last September's Beslan school siege and its precise objective remains shrouded in mystery.
The Russian authorities have made no secret of the fact that the militants tried to seize Nalchik's airport and they arrested one of the attack's planners days before the assault with a detailed copy of the airport plans.
One of the airport's top security officials was later arrested after he confessed to being the "inside man" and to having drawn the map for a relative who told him it was to be used to prosecute a jihad (holy war).
"Russian military contacts and other sources have told us the events in Nalchik apparently were supposed to be only the first phase of a plan that ultimately was to include flying explosives-laden aircraft into high-profile targets elsewhere in Russia," the report said.
"Though the exact targets have not been confirmed, sources say possible targets included the Kremlin, a military district headquarters and railway hub in Rostov-on-Don, a nuclear plant in the vicinity of Saratov, and a hydroelectric plant or dam on the Volga."