The Origin and Destination refer to warehouses. Other warehouses and routes were included, but are not seen in this image.
Note that the cost of the good transported is not taken into account. Common sense would suggest that at a certain point, transporting your coal by aircraft will result in a net-loss.

The following are averages with a 1% margin of error, all upgrades have been researched, and travel time is not taken into account.

• Transporting 1 unit of cargo by air is ~147% as expensive as transporting 1 unit of cargo by truck.
  
• Transporting 1 unit of cargo by train is ~57% as expensive as transporting 1 unit of cargo by truck.
  
• Transporting 1 unit of cargo by ship is ~56% as expensive as transporting 1 unit of cargo by truck.
  
• Transporting 1 unit of cargo by train is ~100% as expensive as transporting 1 unit of cargo by truck.

The following are averages with a 1% margin of error, all upgrades have been researched, and travel time is not taken into account. A full load of cargo is 3 for trucks, 12 for trains, 15 for ships, and 8 for aircraft.

• Transporting a full load of cargo by air costs 717% as much per tile as transporting a full load of cargo by truck.
  
• Transporting a full load of cargo by ship costs 276% as much per tile as transporting a full load of cargo by truck.
  
• Transporting a full load of cargo by train costs 239% as much per tile as transporting a full load of cargo by truck.
  
• Transporting a full load of cargo by truck costs 100% as much per tile as transporting a full load of cargo by truck.

• Trains and Ships should be the backbone of your logistics network because they are, by far, the most efficient [depending on terrain and the cost of infrastructure or terraforming associated with installation].
  
  
• Aircraft do not compete with trains and ships so much as trucks, with both being the most flexible method of transport. Aircraft are the fastest over longer distances, with trains becoming faster as the distance closes, due to the take-off/landing animations.
  
  
• I would advise using ships and trains for request-routes and trucks and aircraft for destination-routes, so as to keep your networks less crowded.
  
  
• Trucks should almost never be used for anything that can be done any other way once traffic becomes a problem; every additional truck does not add a fixed value of congestion, but a multiplicative one, based on how many trucks are already in transit. In practice, this means that separating your gatherer warehouses from your production warehouses [by tier], your city-warehouses and your export warehouses.
  
  
• You'll want to use AUTO-MANUAL-LOGISTIC, and use manual designation only if you can't figure out what the problem is with keeping your goods moving.