What is the easiest way to get from Buffalo NY bus terminal to Buffalo airport and are there airport shuttles?
The easiest way would be to use the airport shuttle.
The quickest and easiest way to get to Buffalo from Toronto is the QEW Hamilton, which changes to QEW Niagara. Take that to the Lewiston Queenston bridge and enter the United States, following the I-190 South until you reach I-290 East. Take the I-290 to the I-90 West to Exit #51E, Route 33. Take Route 33 right to the Buffalo Airport. The Buffalo Airport is about 2-2.5 hours from Downtown Toronto.
There are many ways to get downtown. The easiest and cheapest is taking the MBTA silver line. It brings you from the Terminal to South Station. Once you get there you can take the subway or a bus to anywhere in the city. You can also take a taxi and there are many shuttle busses that you can make a reservation to get to your hotel