There are 5 Christen Industries PITTS S1S aircraft on the U.S. registry that TailWiki has a page for. Every one is built from the public FAA record — year, serial, engine, home base, and registration history — and owners and pilots add photos, trips, and stories on top. The ones listed here were built between 1999 and 2002.
N540PS
2002 Baker Donal E PITTS S1-11B
Dulles, VA
N1972P
2001 Novack Gary A Sr PITTS S-1-E
Indiana, PA
N24SX
1999 Young David E PITTS S-1
Snellville, GA
N8M
1999 Teach Ted L PITTS S1-D
New Carlisle, OH
N925PK
Bohner Phillip W PITTS 12
Pagosa Springs, CO