Gravity keeps us land-bound, most of the time. But there are at least two transportation technologies that work with rather than against gravity: cable-cars, which use the weight of anything they are carrying downhill to help lift anything they are carrying uphill; and gliders/parachutes, which mainly travel downhill.
The use of cable-cars is limited by their low carrying capacity (relative to trains, trucks, ships, etc.). The use of gliders and parachutes are limited by danger and imprecision, and by the fact that they must still fight gravity in order to get aloft in the first place.
New technologies may overcome these limitations, at least to a certain extent. In the case of cable-cars, low capacity can become less of a problem as a result of automation, not just in the operation of the cable-car but also in the loading, unloading, and warehousing of goods using the cable car. A cable car system could then run 24-7 (cable-cars are very quiet, so they are not annoying to run at night), with trucks being autonomously unloaded at the entrance of the cable-car and then autonomously unloaded and re-loaded onto another autonomous truck at the exit of the cable-car. Similarly, automation could allow a passenger to disembark his or her autonomous-valet-parking car or bus to get on a cable-car, then have another autonomous-valet-parking car or bus waiting for him or her at the cable-car’s exit.
Autonomous capabilities could be even more useful for cargo-carrying gliders or parachutes, helping to overcome the limitations of danger and of imprecision. The US military has been making great strides in this area in recent years in Afghanistan, with systems like JPADS (joint precision airdrop system) and research into gliders.
Of course, these systems must still use aircraft get airborne in the first place, which is not sustainable from either an economic or environmental standpoint. This is where things get interesting. What if, instead of gliders or parachutes being released from aircraft, they were instead released from cable-cars? In a mountainous or archipelagic region, this could allow goods and people to be transported during times when roads or ships are temporarily out of service as a result of snowfall, flash flooding, avalanches, earthquakes, low tides, etc.
Cable-cars might similarly be able to work well with cargo drones in general. They could serve as a sort of ferry for drones. By landing on a cable-car, drones could reduce their energy expenditure, recharge their batteries, and, as a result, reduce their battery sizes.
Future Economics 