Every single one of your numbers can be orders of magnitude off. Many people search without buying, there can be hundreds or thousands of fares for a single flight, and industry margins are razor thin. If you're lucky enough to actually get a commission (unlikely), your percentage will still be junk. Skyscanner (much bigger than you) is earning in the single digit percents and I have no doubt there's a cap in many of their agreements.
Pretty much any other computing service has a better ROI.
Pretty much any other computing service has a better ROI.