Yes. AgileMD was designed and engineered to deliver resources to you, even while you are offline.
Once you install the app and choose your resources, AgileMD downloads a local copy of each file to your device. When connected, the app periodically checks for updates and applies any changes as needed. If the app is disconnected (or put in Airplane mode) you will have access to everything downloaded while you were online. In addition, the Search feature will automatically switch from searching the AgileMD universe of files to searching only files available on the device.
Any notes you create while offline will similarly be saved to your local file storage. Once a connection is established, all notes will securely sync to your main account storage so that you can retrieve them on other devices or restore the app on a new phone.
One important caveat: the app cannot load links to webpages while the device is operating in offline mode.