They move more planes at JFK then they do at DTW with less runways.
Not according to the FAA. JFK can handle less traffic than any DAL hub:
Capacity at JFK: 75-87 flights per hour in VFR and Marginal weather, and 64-67 flights per hour in IFR weather.
Capacity at DTW: 184-189 flights per hour in VFR weather, 168-173 flights per hour in Marginal weather, and 136-145 flights per hour in IFR weather.
Capacity at ATL: 180-188 flights per hour in VFR weather, 172-174 flights per hour in Marginal weather, and 158-162 flights per hour in IFR weather.
Capacity at MEM: 148-181 flights per hour in VFR weather, 140-167 flights per hour in Marginal weather, and 120-132 flights per hour in IFR weather.
Capacity at MSP: 114-120 flights per hour in VFR weather, 112-115 flights per hour in Marginal weather, and 112-114 flights per hour in IFR weather.
Capacity at SLC: 130-131 flights per hour in VFR weather, 110-120 flights per hour in Marginal weather, and 110-113 flights per hour in IFR weather.
Capacity at CVG: 120-125 flights per hour in VFR weather, 120-124 flights per hour in Marginal weather, and 102-120 flights per hour in IFR weather.