Covering your model is one of the last things you do, it's also one that requires a lot of consideration if you want a result that's going to handle the loads imposed by the model as well as look good. Which covering material you select will be based on numerous factors, including the following;
  • Fuel proofing
  • Weight
  • Strength
  • Colour availability
  • Pricing
Note that even with the same covering there can be a reasonable deviation in the weight (per metre square) due to the mass of the pigments in the material, different colours have different weights.

CoveringWeightApplication methodDetails
Japanese tissue 7gsm Dope One of the lightest coverings you can obtain. Note that this will require adhesive to apply to the airframe and doping or similar sealing.
Laminating film ??? Iron-on Typically available in 1.5, 3, 5 and 10mil thicknesses, laminating film is an excellent low cost source of plastic type covering film. Even in the 1.5mil thickness laminating film exhibits exceptional strength to weight ratio.
Nelson Lite Film
So-lite
Solite
21gsm Iron-on Considered to be one of the better iron on ultra-light films.
Litespan 30gsm Iron-on Litespan is a very light synthetic tissue used in place of normal tissue/dope. It is much stronger and tougher and doesn't need dope. Fuelproof as ironed-on.
Coloured Micafilm 40gsm (25gsm for transparent) Framework is painted with heat-activated glue like Balsarite  
Fibafilm 42gsm Iron-on Fibre-reinforced polyester film. Fibafilm is ideal for 'old timer' models, sailplanes, 'electrics' and any model that needs a lightweight covering that will stiffen the framework
Solarfilm 55~60gsm Iron-on Solarfilm is a plastic film covering (polypropylene), and is available in a wide range of solid, metallic, transparent and fluorescent colours and in a variety of sizes. It is easy to use with good shrinkage. Iron on and shrink tight with extra heat.
Solarspan 60~65gsm Iron-on Self-adhesive plastic film. Solarspan is a thicker, stronger version of Solarfilm. It gives a smoother finish and is easy to work round wingtips etc.
Monokote 65~75gsm Iron-on Considered to be a rather heavy covering for most park planes, Monokote is however rather tough and easy to use.
Econokote gsm Iron-on Low temperature version of Monokote
Ultracote 70~90gsm Iron-on  
Glosstex 115~125gsm Iron-on Glosstex has a high-gloss two pack paint finish, is fuelproof.