Bolt Action newby question re: Artillery vs. Forward Observer

[Doug E]

Does the player have to have actual piece of artillery somewhere on the table for the Forward Observer to call it in?  Or is the FO getting it from somewhere off table? 

Trying to apply common sense here.  The rules for an FO calling in air support imply you don't need to purchase an airplane with your points.  I've never seen an airplane for sale in the book or any of the supplements.  Also, different roles of the dice result in assistance from different types of planes, and Americans get two airplanes responding instead of one.  Hence, six airplanes would be required.  So yeah, I'm fairly confident I don't have to have any airplanes tied to the ceiling.

So, if you don't need to purchase a howitzer with your points, why would you purchase a howitzer instead of just a forward observer?

More importantly, did I miss where this is explained in the rules, or is it just implied because nobody thought it was worth explaining?

Thanks for your help.

[voltan]

Forward observers call in a strike from off table resources so you don't need anything but the observer figure and a marker for where you want the strike to land, on table artillery pieces work differently, they can fire direct or use their own spotter figure to fire indirectly, using the spotter to work out line of site stuff. The observer's artillery only fires once but the on table can fire every turn. Sorry can't remember where it's all explained, been a while since I've played or looked at the books.

[Vanth]

I have always found FOs a big waste: one shot, very situational and most of the time they do nothing, to the point that I stopped taking it even when it was free...

[Doug E]

Thank you for  your responses.  It sort of makes sense now.