Just to muddy the waters a little see part of the article I found. Matt Jefferies was the art director for the original series.
http://www.neatorama.com/2009/06/15/8-starship-enterprise-facts-every-trekker-should-know/
The Origin of NCC-1701
How did the famous USS Enterprise get its registration number NCC-1701 is the stuff of legend. There are conflicting stories, including one where 1701 is a tribute to Roddenberry's childhood neighbor's house number or that Jefferies got it from the registration number of his airplane.
Here's Matt Jefferies' explanation when he was asked during a BBC Interview:
NC, by international agreement, stood for all United States commercial vehicles. Russia had wound up with four Cs, CC CC. It’d been pretty much a common opinion that any major effort in space would be two expensive for any one country, so I mixed the US and the Russian and came up with NCC.
The one seven zero part - I needed a number that would be instantly identifiable, and three, six, eight and nine are too easily confused. I don’t think anyone’ll confuse a one and a seven, or the zero. So the one seven stood for the seventeenth basic ship design in the Federation, and the zero one would have been serial number one, the first bird.