To be honest, i have always found a telescope to be better, particularly for high altitude aircraft etc. Not sure what your budget is, but i've always used Kowa Scopes. The one i have now, the Kowa TS
-801, is an excellant scope and cost me in the region of £140.
The 16 refers to magnification, anything more that 20x and you'll need a tripod, which for overflight is impractical. The 50 refers to the size of the lens in mm. The larger the size the more light it lets in and gives a clearer image.
Hope this helps