I'm only playing in V1.2 world at the moment, so I apologise if 1.3 covers this. However, I have had issues in the past and again recently over extending leases of aircraft from other players, in terms of whether they allow extensions or not, and also changing the setting after lease. Two linked requests therefore:
1 On the leasing page, a flag showing whether lease extension is allowed
2 If the owning player changes the option, a message is automatically sent to the leasing player to advise them of the fact.