Massive intelligence sharing, much of which is related to counter-terror operations that is best not discussed too much. Extensive cooperation in designing, testing, developing advanced weapons systems,missile detection systems, advanced radar systems. These systems cost billions to develop, and “getting it right” is essential. Some years ago, Israeli pilots were training USAF pilots out in the Arizona desert and elsewhere in the extremely difficult and dangerous low-altitude flying technique they use to avoid enemy radar; something the IAF had developed several decades ago and continues to upgrade as needed.
There are other areas of cooperation in non-military matters, such as alleviating the drought in California by introducing “drip technology” irrigation techniques, and water desalination.
Tiny enough?