I love to travel and often times I have to go to somewhere. This search allows me to plan additional stops in between my origin and destination. As an example, if I want to fly from Amsterdam to New York you can take a direct flight, or add a stop somewhere and add that destination as another stop. So maybe you could visit London for a few days, or Washington or maybe Bermuda.
Another one I am working on is https://startenv.com, this one will automatically convert your docker compose file to a test/staging environment whenever you create a PR or for specific branches. This way your QA or clients can give feedback for a specific feature before you release it. I've been using it for a few weeks and I am really liking it (but of course I am biased).
While TwinFlights is a side project I am hoping to turn StartEnv into a proper B2B SaaS. If you think this could fit your business, please reach out to me and I'll do my best to make it worth your time. :)