Bicycling to the Airport
This is the most money saving trip you can possibly make on a bicycle. It is 19 km from where I live and I make it in just over an hour for my faster times. The longest time was 1:45 under difficult winter conditions. That isn't fast by bicycle speed demon standards but is decent enough by mine. Of course having a suitcase on each end of the handle bars does slow you down a bit.
Actually my luggage is a backpack that has a flap all the straps can zip up in, and then it looks like a fabric suitcase and has a handle in the appropriate place. I tend to travel light and sometimes only have my carryon bag. When I do have the backpack too, there has always been room for my carryon inside it until we get to the airport. It is a really handy luggage arrangement and I have sometimes walked a few miles with luggage in countries where taxi drivers are a pain in the neck. This made it easier.
At the airport the (free) bike rack is about 50 meters from the main entrance. Compared to vehicle parking this is the super deluxe arrangement. I have a simple stainless steel pocket knife that I got for $5 about 30 years ago. Because it is always with me on handyman jobs or around the house, it might be the most used tool I have ever owned and I do like it. I even have it on my travel check list to put it into my checked bag but just once I realized that I was at the airport with no baggage to check and still had the knife on me. I ran back out to my bike and put it in a small old bag attached to the handle bars. Security didn't get to take it away and I still have it.
So compared to parking rates at the airport, taking the bike saves me a lot of time compared to the hours that I would have to spend working to pay for parking. Or in other words, it's faster.