I never cease to be amazed at the wonder that is modern air travel. Even though I’ve been flying since I was a child, I still marvel at being served coffee while traveling at 540 miles per hour 37,000 feet above the ground. Becoming blasé about this stuff is hard.

The machine that makes this miracle possible — the jetliner — is a complex system composed of complex sub-systems: avionics, fuel, engines, communications, air conditioning, pressurization, radar, auto-pilot, toilets, etc. Yes, there’s even a percolator.

The aircraft, in turn, is part of a broader system that includes air traffic control, maintenance, pilot and cabin crew training, catering, fueling, national and international regulations, etc. Private companies operate some of these systems, and government at various levels (local, state, national) operate others. Sub-contractors and unions provide various services to both. With all these complex systems interoperating, and all the parties that take part in making it happen, it’s amazing that air travel is possible at all.

Most times I arrive at my destination without having thought about the moving parts that made the trip happen. However, when one of the systems breaks down the complexity behind the scenes emerges. Recently, I was on a flight that was delayed for almost an hour because the system the starts the airplane’s engines failed. The captain kept us appraised of the situation: ground crew checked out the system and eventually got it started. Then we had to wait for data to be transmitted to the airplane from a remote location. (This step was necessary because conditions changed as a result of our delay.)

I didn’t have visibility into all the stuff that happened behind the scenes, but from what I could gather there were a lot of dependencies at play. Some were things that needed to happen on the plane; some needed to happen at the airport; some needed to happen remotely. Overcoming one problem triggered another step in the process; systems had to come back online in a particular order before we’d be clear to take off.

It’s easy to become frustrated when breakdowns cause delays. That said, I also find them fascinating. Breakdowns offer glimpses of the seams in a complex system that’s usually hidden from us and which results in safe, fast, and inexpensive long-distance travel.