This manuscript presents evaluation results of hexagonal Y1-xRxMnO3+d (R = Er, Y, Dy, Pr, La, Tb and Ho) rare-earth manganites for prospective air-separation applications. The reversible oxygen storage characteristics of HoMnO3+d and related materials shown by the fast incorporation and release of interstitial oxygen at easily accessible elevated temperatures of ~300 oC demonstrate the feasibility and potential for low-cost thermal swing adsorption TSA process for oxygen separation and enrichment from air.