Laboratory measurements of O2+(X2IIg) and O2+(a4IIu) in charge transfer with NO have been carried out from 300 ¿K to ~1 eV relative kinetic energy. The 300 ¿K rate constants are 4.4¿0.5¿1010 cm3 s-1 and 11¿3¿10-10 cm3 s-1, respectively. Most earlier measurements of O21-NO charge transfer involved an unknown mixture of ion states and yielded values too high to be appropriate to the ionospheric E region.