Velocity-modulation Fourier transform emission spectra from a N2O/He discharge plasma recorded between 1 and 5.5 mu m are described. Surprisingly, they show Doppler-shifted lines for the E(2)Sigma(+)-D(2)Sigma(+), C(2)Pi-A(2)Sigma(+), and D(2)Sigma(+)-A(2)Sigma(+) Rydberg-Rydberg rovibronic, transitions of the nitric oxide neutral molecule. These polarity-dependent Doppler-shifts are those of positively charged particles. Vibration-rotation lines of NO and transitions from other neutral molecules like N-2 are also present in the spectra with comparable intensities and remain unshifted. Experimental investigations and possible explanations are discussed. (c) 2005 Elsevier B.V. All rights reserved.