In this paper , we report on high angular resolution radio observations of the planetary nebula NGC 6881 obtained with the Very Large Array at a wavelength of 6 cm .
The emission appears to be the superposition of a roundish core and a point-symmetric bipolar structure elongated along a position angle of about 145 ^ { \circ } .
This is strongly reminiscent of the morphology seen in H \alpha and [ NII ] images .
A comparison between VLA observations obtained in 1984 and 1994 clearly reveals the expansion of the core of the nebula , at a rate of 2.1 \pm 0.7 mas yr ^ { -1 } .
Assuming that the expansion velocity in the plane of the sky ( determined from these measurements ) and the expansion velocity along the line of sight ( estimated from optical spectroscopy available in the literature ) are equal , we find a distance to NGC 6881 of 1.6 \pm 0.5 kpc \pm 0.3 kpc , where the first error reflects the uncertainty on the expansion , and the second error comes from the potential difference between pattern and material speeds .
This distance is compatible with ( but does not necessarily imply ) an association of NGC 6881 with the nearby HII region Sh 2-109 and , more generally , the Cygnus star-forming region .