A lengthy discussion of Yeats' relationship to Gregory suggests that it was way more complicated, and combative, than Yeats' poems suggest.
This is a great web resource about the Great War.
Yep, they definitely had planes (and cameras) during WWI.
If you feel like taking a literary tour of Ireland, check this out.
Yeats' page at the poet's graves website.
Check out a fantastic animation and narration of the poem.
Here's another cinematic interpretation.
This is just… awesome. The infamous Pogues frontman puts his own unique spin on the poem.
This guy goes all out and really captures the tone of the poem.
Check out this series of recordings of Yeats reading his own poems.
Here's a picture of the older Yeats, looking really serious.
Here's the young W.B. Yeats.
Here's a picture of the house at Coole Park, where Yeats and Robert Gregory spent much time.
Check out a picture of Yeats' grave.
Here's a picture of Lady Augusta Gregory, Robert Gregory's mother and friend of Yeats.
Yeats was also very involved in writing and producing plays. Here's an interview in Theatre Arts Monthly with him about that work.
Here are the collected poems of W.B. Yeats.
Robert Gregory's plane has got to be in here somewhere.
Check out all the plays and poems that have been adapted to the big and small screen.