▲ ▼ Aerial imaging through commercial airplanes
There's still money on the table for airline operators where routes are concerned. It sounds a bit fringe, but most of these flights take off and land at airports in large cities. International airports are often zoned around industrial centers that are typically set off away from the city core. Coupled with the high frequency of inbound and outbound traffic depending on the airport, commercial flights are excellent candidates for capturing high resolution aerial imagery in near-real time. In many cases, those images can be transmitted back down while the plane is in the air thanks to in-flight internet.
There have been past attempts to harness the passive residual capabilities of air travel for photography, but none have stuck based on the difficulty of scaling such a system. If successful, crowdsourced aerial photography for cartography could add a layer of temporal resolution we just can't achieve with fewer than 500 imaging satellites currently in orbit, and for 1/10,000th the cost of satellite-based imaging. Add on concerns about LEO crowding and the thousands of use cases near-real-time aerial imaging could provide at a fraction of the cost, it becomes an interesting problem to solve.
There are plenty of barriers to this kind of scheme, regulation in particular, that could keep airlines from participating; the first major carrier who does, however, may find themselves with a new multi-billion dollar revenue stream.
Considering the use for up-to-date mapping is growing exponentially due to navigation related apps there could indeed be a need-gap for aerial real-time imaging through commercial airplanes.