Seems this hasn't been covered here yet...
Estonian Air (OV) is to stop flying between Tallinn and Helsinki in the coming summer season. The reason is that more and more business travelers each year use high-speed catamarans and hydrofoils once they start running after the winter months. These vessels cover the distance between the two city centres in 1½ hours, and while flight time between HEL and TLL is barely more than half an hour, trips between the airport and downtown as well as check-in times at both ends accumulate for a longer total time than with the faster modes of sea transportation. This makes airline profitability on the route questionable for a period of time up to late autumn. We'll see if Finnair, too, will pull a similar decision.
On the other hand...
Copter Action, a Helsinki-Malmi (ICAO code EFHF) based helicopter company, is to start scheduled chopper service between the two cities later this spring. The company has ordered two 14-seat Sikorsky S76C+ helicopters for the route.
It's quite rare anywhere (at least in Europe) to have a route flown with a helicopter, but the short distance between this particular citypair (about 70 km), combined with the fact that no land traffic is possible, made Sikorsky(!) approach Copter Action and suggest they establish regular service. And CA seems to believe in that business, as they're building a passenger terminal at Hernesaari, a harbour/industrial area near downtown Helsinki.