If you're in the circle when the plane starts its maneuver out to return and straffe it will follow you anywhere on the map. All loiters work like this to my knowledge. Now if you think about loiters only effecting the circle and the circle alone and any tank or infantry that left the circle has it's straffe canceled straffes would be absolute trash. They'd have to have their costs lowered immensely to justify how quickly you can exit the circle. Especially with speed boost mechanics.
When if its tracks your tanks to outside the circle well should I say:
"Well this is definitely fine, a ability that goes beyond my control whether or not my tanks gets murdered because logic"
Why shouldn't arty callins extend beyond their AOE as well? I mean, its supposed to be powerful.
I'm fine with abilities that actually work within their set of rules, I don't get to defend an ability that clearly went over the rules to be effective. Hell, we don't even know if the tanks are still targeted in the UI by those planes.