Lyft is a Delta SkyMiles Auto Partner and you earn one Delta SkyMile for every $1 you spend with Lyft. However, through August 31, 2017, you can earn 3X miles per $1 spent with Lyft for rides to and from the airport. You need to link your Lyft account with your Delta SkyMiles account to take advantage of this offer. You can link your accounts here.