The 20-year-old signed a new contract with the Bees earlier this year but has made just two substitute appearances so far this season.
Bees Academy boss Ose Aibangee told the club website: "Aaron is at the stage where he needs to play competitive first-team football.
"Cambridge are offering him a great opportunity to train at a good level and play in games that are extremely important.
"This will be great for his development and we will see how he goes over the next few weeks."
- Sports & Recreation