only you wont be a rocket because you will have wind drag and wont be able to ride through any gaps.
i rode form waterloo to liverpool street and back today with a wheel bag on my shoulder.
on the way there it was like a sail and on the way back it kept me from going through any gaps i would usually do an made it very hard for me to destroy the hipster i was racing (which i still did despite my shoe coming out of one of my clips and having to wait to go through a lot of traffic) and overall probably added about 10 minutes onto my journey
were you riding with a disc wheel???