LGA-BOS and LGA-DCA are the official Delta Shuttle routes.

On weekends however, when LGA-BOS/DCA operate on a reduced frequency basis, the Shuttle MD88s are often deployed on other domestic routes with little premium traffic (such as from JFK/LGA/BOS to Florida or JFK-BOS). On those routes, they don't actually offer the Delta Shuttle product; it's regular domestic service but with the Shuttle planes (with increased pitch for everyone).