"The intelligence agency, called the Bundesnachrichtendienst (BND) discovered that some calls on Air Force One were unencrypted and it was able to tap into radio frequencies that were used for those calls, according to the book, "
No hacking or deployment of listening devices, just passive listening. Unless you have other sources?
As per the article linked above (https://archive.ph/kCxNw)
"The intelligence agency, called the Bundesnachrichtendienst (BND) discovered that some calls on Air Force One were unencrypted and it was able to tap into radio frequencies that were used for those calls, according to the book, "
No hacking or deployment of listening devices, just passive listening. Unless you have other sources?