As if the time travel in time travel. Thanks to the combined efforts of Tony Stark, Bruce Banner and Scott Lang, the Avengers hatch a plan to scatter throughout time and take Infinity Stones from the past to put things right in the present.
This proposed time heist sets up a scene where Rhodes, Banner and Lang are discussing the mechanics of travelling through time with Clint "Hawkeye" Barton and Nebula. As they prepare to test out their prototype Quantum Realm suits, the gang are attempting to figure out the exact principles of changing the past, essentially explaining to the audience why they can't just go back in time to when Thanos was a cute, purple, Josh Brolin-voiced baby and take him out of the equation - a suggestion nobly put forward by Rhodes himself.
In their attempts to wade through the "rules" of time travel, the group uses iconic time-bending movies as reference points, since these are the main sources of knowledge on the subject for both the characters and the audience. A Wrinkle in Time.
Mentioned by War Machine, Disney's A Wrinkle In Time hit the big screen in 2018 and, despite receiving Green Lantern in a list otherwise full of great superhero movies. However, perhaps an even more glaring issue is that there's no way War Machine has seen, and is then willing to it to have seen, A Wrinkle In Time. Rhodey can't even use the excuse of having children to justify why he's seen it - not that any of the other Avengers seem to care anyway.
It's hard to imagine War Machine, on a break between missions prior to the events of Avengers: Infinity War, decided to take a well-earned break and treat himself to a cinema trip to see A Wrinkle In Time when the film hit theaters in February 2018, and it's only marginally easier to picture him watching on DVD, alone in Avengers HQ, desperately trying to console himself after Thanos' snap. A far more likely explanation for this out-of-character reference is that Disney saw a discussion about time travel movies in the Avengers: Endgame script and wanted one of their own in there.
While this doesn't take away from Avengers: Endgame being a fantastic movie, is does act as a nagging reminder of the three-fingered, white-gloved hand that ultimately pulls the strings in the MCU.
