Friendly Airports for Mothers Act of 2017 This bill authorizes the Department of Transportation (DOT) to approve a grant application for an airport development project only if the DOT receives written assurances that the owner or operator of a large or medium hub airport will maintain a lactation area at each passenger terminal building of the airport behind the airport security screening area. The bill defines "lactation area" to mean a room or other location in a commercial service airport for members of the public to express breast milk that: is shielded from view and free from intrusion from the public; has a door that can be locked; includes a place to sit, a table or other flat surface, and an electrical outlet; is readily accessible to and usable by individuals with disabilities; and is not located in a restroom. DOT may approve a terminal development project for the construction or installation of a lactation area at a commercial service airport.