I ride 20miles round trip to work and 20 miles round trip to school 3-5 times a week. A picture of my bike is attached. Its a 1972 Gitane frame with mostly original parts except for new rims with a rear flip flop hub. (This picture is midway through stripping the paint. Now it's clear coated steel.) Tires are 28 conti contacts. Gearing is currently 52x17 for 82". Perhaps because I'm still young, or perhaps because of my desire for efficiency, I want to go fast on my commute. I dont have a bike computer but based on my commute times and google maps I'm averaging 20ish with relatively few stoplights.
Currently, I shove my stuff in my High Sierra school backpack. Normally I have school supplies, a change of clothes for work, maybe a pair of shoes or tupperware containers. I'm in New Orleans, so there are no hills but wind can be a serious issue. I've got a pretty aggressive position on the bike and when the backpack is full it seems to act like a parachute on my back. My question is: Is there another way for me to schlep my stuff around without having such a drag penalty?
The frame has no braze-ons for racks. In addition, I have to worry about bike theft quite a bit so I'm thinking any sort of stuff hanging off the bike, unless it goes with me when I dismount, is off limits. Most bags are rated based on comfort and carrying capacity but they aren't my primary concern. I'm looking for something thats more aero than my current bag. Any thoughts?