Belgian air force base during the early war years 1914-15. Probably <a href="https://en.wikipedia.org/wiki/Farman_MF.11" class="extiw" title="en:Farman MF.11">Farman MF11</a> planes
<a href="//commons.wikimedia.org/wiki/User:Ad_Meskens" title="User:Ad Meskens">Ad Meskens</a>
<span class="int-own-work" lang="en">Own work</span>