No. There are not any grocery stores in downtown/Bricktown. I guess they could, hopefully, take the streetcar to the river taxis, take it to Meridian and then take another transportation means to the airport from there. That would probably be a three-hour trip, though.
Would it take them to places of likely employment? I would reckon that most who work downtown are degreed professionals, not likely to live in northeast Oklahoma City. In reality, the rail streetcar system will do little to serve the poor, impoverished and the relatively few in OKC that do not have a vehicle.