The movie Fly Away Home is fiction.
http://www.epinions.com/content_30385213060
But the idea of Canadian Geese following an ultralight is done for real,
to teach them new migration patterns.
www.operationmigration.org
(also search the web for many interviews with "Bill Lishman")
"Most waterfowl learn the migration route and its destination wintering area from their parents. If birds are orphaned or raised in captivity and then released, they will not migrate. They join the resident population and fight for survival in the harsh northerly winters.
All of this is a particular concern for endangered species. To ensure their survival, birds are often raised in captivity. Once mature, the healthy birds can be released into the wild; however, they need to be taught a safe migratory route."
Many excellent photos at:
http://www.operationmigration.org/photo%20journal%20mig-02.html
Many species are now involved, including whooping cranes:
http://www.operationmigration.org/work_wcranes.html
"It is believed that approximately 1,400 whooping cranes existed in 1860. Their population declined because of hunting and habitat loss until 1941 when the last migrating flock dwindled to an all-time low of 15 birds. The wild flock has slowly increased to over 180 in late 1999. "
Since then, others have started the Trumpeter Swan Migration Project
http://www.trumpeterswans.org/TSMP.html
Interview at:
http://www.earthsky.com/2002/esmi020126.html