Reports in Canada make it sound like Air Transat could have gotten assistance for the plane, despite all the other planes (20 or 30, not clear) that diverted to Ottawa (only a medium sized airport one might say).
"The airline said the airport staff were unable to provide bridges to allow the plane to be unloaded and there were delays both in refuelling the aircraft and refilling the drinking water reservoir.
The Ottawa International Airport Authority disputes those claims, saying closer to 20 planes were diverted and all other planes were refuelled and on their way within three hours, most within the first hour or two.
The airport authority said there was both a gate and air stairs available, and they were prepared to bring supplies beyond just bottled water to the stranded passengers — but never received clearance from Air Transat."
So there's a bit of a war of words about who was responsible for what.
As for what "rights" passengers might have:
"In a written statement Wednesday, the transportation agency said it was launching an inquiry to determine whether Air Transat respected its tariff — a document that sets out, among other things, an airline's rights and responsibilities toward its passengers.
According to that tariff, in the case of an on-board delay more than 90 minutes, Air Transat promises to offer passengers the option of getting off the plane."
Source:
How paramedics responded to 911 calls from Air Transat passengers stranded in Ottawa - Ottawa - CBC News