At least an interline and a bilateral FF (Earn and Burn) agreement to start off with.
They won't be codesharing at this stage (taking into consideration the failed AA/B6 alliance application which included codeshares).
UA and B6 will be planning to swapping some JFK and EWR slots, enabling UA to restart JFK-LAX/SFO services in the future.
thepointsguy.com
They won't be codesharing at this stage (taking into consideration the failed AA/B6 alliance application which included codeshares).
UA and B6 will be planning to swapping some JFK and EWR slots, enabling UA to restart JFK-LAX/SFO services in the future.

United Airlines and JetBlue to team up in new, blockbuster partnership - The Points Guy
Major news on the airline front: United Airlines and JetBlue will partner in a new alliance called "Blue Sky."