Aircraft tow system

1. A cargo transport system comprising:

an engine powered tractor aircraft;

at least one unmanned autonomous towed aircraft, which is connected to the tractor aircraft for inflight towing by the tractor aircraft, wherein the towed aircraft includes a body with wings positioned on opposing sides of the body;

a sensor system configured to sense flight parameters including relative positions of the tractor aircraft and the towed aircraft;

at least one towing element comprising a cable coupled between the towed aircraft and the tractor aircraft; and

an auto pilot system in the towed aircraft configured to receive the sensed flight parameters from the sensor system, wherein the autopilot system is configured to autonomously control taxing, takeoff, flight, and landing of the towed aircraft, and wherein the autopilot system is configured to maintain, based at least in part on the sensed flight parameters, positions of the towed aircraft and the wings with respect to the tractor aircraft at specified positions for positive energy wake gain above a turbulence vortex produced by the tractor aircraft during flight, and wherein the position of the towed aircraft with respect to the tractor aircraft is controlled, at least in part, by adjustment of a length of the cable coupled between the towed aircraft and the tractor aircraft.

2. The cargo transport system of claim 1 , wherein the length of the cable is adjustable based on one or more of the following parameters: flight state, environmental conditions, tractor aircraft weight, towed aircraft(s) weight, and cable tension.

3. The cargo transport system of claim 1 , wherein the length of the cable is shortened for taxiing, lengthened for landing, and varied inflight to improve flight performance.

4. The cargo transport system of claim 1 , wherein the autopilot system is configured to control a speed of the tractor aircraft to improve flight performance.

5. The cargo transport system of claim 1 , wherein the towed aircraft is configured to power the tractor aircraft in flight.

6. The cargo transport system of claim 1 , further comprising an additional towed aircraft, and wherein the additional towed aircraft is coupled to the first towed aircraft or to the tractor aircraft.

7. The cargo transport system of claim 1 , wherein the wings are sized and shaped to gain lift and thrust from the turbulence vortex of the tractor aircraft.

8. The cargo transport system of claim 1 , wherein the towing element includes a cable sensor configured to measure magnitude and/or direction of tension in the in the cable.

9. The cargo transport system of claim 8 , wherein the autopilot system is configured to maintain the position of the towed aircraft based on, at least in part, the magnitude and/or direction of tension in the in the cable.

10. The cargo transport system of claim 1 , wherein the autopilot system is further configured to control steering, and inflight maneuvering of the towed aircraft.

11. The cargo transport system of claim 10 , wherein inflight maneuvering via autopilot control of the towed aircraft is based on inflight parameters of the tractor aircraft and/or the towed aircraft.

12. The cargo transport system of claim 1 , wherein the towed aircraft carries cargo, an energy storage element, and/or emergency supplies.

13. The cargo transport system of claim 12 , wherein the towed aircraft carries an energy storage element which comprises fuel, hydrogen, and/or a battery.

14. The cargo transport system of claim 1 , wherein the towed aircraft is configured to disconnect from the tractor aircraft inflight.

15. The cargo transport system of claim 14 , wherein the towed aircraft is further configured to land autonomously separated from the tractor aircraft.

16. The cargo transport system of claim 1 , further comprising one or more ram air turbine(s) within the towed aircraft for generating electric power for inflight use.

17. The cargo transport system of claim 16 , wherein the towing element enables energy flow as liquid fuel and/or electricity from the towed aircraft to the tractor aircraft.

18. The cargo transport system of claim 1 , wherein the tractor aircraft is a single tractor aircraft configured to tow the towed aircraft without assistance from another aircraft.

19. The cargo transport system of claim 18 , wherein the tractor aircraft is configured to tow the towed aircraft during taxing, takeoff, and flight without assistance from another aircraft.

20. A cargo transport system comprising:

an engine powered tractor aircraft;

at least one unmanned autonomous towed aircraft, which is connected to the tractor aircraft for inflight towing by the tractor aircraft, wherein the towed aircraft includes a body with wings positioned on opposing sides of the body;

at least one towing element comprising a cable coupled between the towed aircraft and the tractor aircraft; and

an autopilot system in the towed aircraft, wherein the autopilot system is configured to autonomously control taxing, takeoff, flight, and landing of the towed aircraft, wherein the autopilot system includes:

one or more optical sensors positioned to detect a position and an orientation of the tractor aircraft;

a computer processor coupled to the optical sensors; and

a memory coupled to the computer processor, the memory storing instructions executable by the computer processor to:

implement at least one computer vision algorithm to track a position and an orientation of the towed aircraft relative to the tractor aircraft based on the position and the orientation of the tractor aircraft detected by the optical sensors; and

maintain, based at least in part on the position and orientation tracked by the at least one computer vision algorithm, a position of the towed aircraft with respect to the tractor aircraft at a specified position for positive energy wake gain above a turbulence vortex produced by the tractor aircraft during flight, wherein the position of the towed aircraft with respect to the tractor aircraft is controlled, at least in part, by adjustment of a length of the cable coupled between the towed aircraft and the tractor aircraft.