You can use the Save as command to save individual messages in Text or HTML format. To save multiple messages, you'll need to use VBA or a utility. See Tools for a list of utilities that can automate the process and save messages in a variety of formats.
For a small fee, Southwest Airlines' Early Bird Check-In allows passengers to check-in to a flight automatically up to 36 hours prior to the flight's scheduled departure time.
The only bird known to make use of infrasound (at about 20 Hz) is the western capercaillie. The hearing range of birds is from below 50 Hz (infrasound) to around 12 kHz, with maximum sensitivity between 1 and 5 kHz. The range of frequencies at which birds call in an environment varies with the quality of habitat and the ambient sounds.