MCU: 10 Fascinating Facts Behind The Avengers (2012)
6. The Rotor Long-Game Gag
Some of the small observations that are never openly acknowledged in the MCU are the best things about it. We often see things seeded in one film that end up playing out elsewhere just outside of the main focus.
The Avengers has one of those moments as we see Iron Man attempting to fix the destroyed rotor of the SHIELD Helicarrier by flying into it. Naturally, it doesn't go quite as smoothly as he would hope and his suit ends up being damaged.
By the time Captain America: The Winter Soldier comes around, SHIELDS Helicarriers have been fitted with rotor-less turbines that Stark developed to make sure it never happens again.
In another great little Stark design detail, when he pulls out blueprints for Avengers Tower, they include personal quarters for each member of the team, denoted by a symbol (Iron Man's mask, Cap's shield and Mjolnir notably)...