For missing instructions or box content

[Ryan K]

One more for your older kits, a number of Testors/Italeri kits.

https://www.facebook.com/Plastic-Model-Kit-Instructions-1429829590656282/

[Ronv]

Cool!
RonV

[Ryan K]

Some more resource

http://www.fcmodeltips.com/2013/10/manuales-de-montaje-de-maquetas-models.html

https://www.scalemates.com/kits/
An example https://www.scalemates.com/kits/102231-revell-04194-fokker-d-vii
Below the 'Decal options', there is a section 'Instruction sheets' with a pdf attached. This is relativity new function or use so results can be spotty. 

[Ryan K]

If your looking for instructions or box content here are the sites I use.

Two main sites
http://www.1999.co.jp/eng/
http://www.model-making.eu/

Some others
http://www.luckymodel.com/
http://www.towerhobbies.com/

For Aeromaster or Eagle Strike decal placement guide
http://www.squadron.com/ProfileSearch.asp?Submit3=Go