>>29353356
At the beginning the Nazgul were on horses. Its a long trip from Mordor to the Shire even on horseback so Gandalf could have taken the eagles while they were fucking around on horses and covered way more ground by the time the Nazgul got back to Mordor to mount up. Unless they had the fellbeasts on standby while they were on horses, which is a stretch. Also, it only takes like 1 minute tops to walk into mount doom from the entrance, chuck the ring into the lava, and bounce so even just a 30 minute head start would put them ahead of the Nazgul. They could've even crashed into the entrance on a suicide mission to do it. Its the fate of the world, at least one person would be willing to dive into lava to save all life in middle earth