Me: "So, if the eagles could fly in and get Frodo and Sam out, why couldn't they have flown them in in the first place?"
RX: "See, they needed the chaos of the destruction of the Ring to cause a Disturbance in the Force and throw Mordor's 'Chain Home' radar stations into disarray..."
Me: "Ah. Or else they could've been shot down by a SAM on the way in?"
RX: "Or eaten by a Grue, more likely."