I would like a comprehensive list of all the grass airstrips in the
state of Indiana that serve ultralight airplanes

Hi there,

I found an excellent resource called AirNav, which has in-depth
information on US airports. After sifting through the listings, I
found the following Indiana grass airstrips which are UL friendly:

Larsh Airport, Colfax
http://www.airnav.com/airport/5L7

Hangar Fly Ultralight Club, Lawrence
http://www.airnav.com/airport/4II2

Action Airpark, Hardenstown
http://www.airnav.com/airport/I38

Gerig's Field Airport, Roanoke
http://www.airnav.com/airport/2IN2

Baird-Wolford Airport, Tipton
http://www.airnav.com/airport/2II6

Stuntz & Hochstetler Pines Airport, Walkerton
http://www.airnav.com/airport/59IN

A complete list of UL friendly airports in the USA can be found at
Friendly Fields, part of a defunct website, but viewable via the Web
Archive:
http://web.archive.org/web/20011031081748/http://www.seaquest1.com/trikestories/friendly_fields.htm

All Indiana airports, as listed at AirNav:
http://www.airnav.com/airports/us/IN

While looking for the grass airstrips I found some other info that
might be of use to you - Indiana flight parks, UL clubs and a book.

Larsh Flight Park 
Phil & Carla Larsh 
11470 West 800 North 
Colfax, IN 46035 9636 
(317) 324-2424 

Boyer Flight Park 
Bob Boyer 
RR1 Box 143 
Burnettsville, IN 47926 
(219) 943-3552 

Indiana's First UL Club
Mark Schwyn  
Ashley  
Indiana 
(219) 587-9435
Email:ulflyer1@yahoo.com  

Hoosier Flyers  
Carla Larsh  
Colfax  
Indiana 
(765) 324-2424 
Email:clarsh@tnni.net   

Nulltown Wingnuts Inc  
Tom Robeson  
Cambridge City 
Indiana 
(765) 478-5453 
    
Terre Haute Ultralight Club  
Mike Perkins  
Terre Haute  
Indiana 
(812) 234-4398 

There is a book on this topic - covers which airports permit
ultralight activity and which ones don't allow it:

Ultralight Vehicles: Access in the General Aviation Environment - A
Handbook for Ultralight Pilots (and Other Interested Folk)

A review of it is at UltraLight Homepage (scroll to the bottom):
http://www.ultralighthomepage.com/friendly.html


Search Strategy:

I went straight to Google Directory and surfed from there:
http://directory.google.com/Top/Recreation/Aviation/Aircraft/Ultralight/

I trust this answers your question. Feel free to ask for any
clarifications you may require.

Best wishes,
robertskelton-ga