The behavior of a sound wave is affected by the density of the medium, the temperature of the medium and the pressure of the medium if it is a gas. Motion of the medium independent of the sound wave may also affect the way sound propagates.
Yes, you may check-in for your Delta Air Lines (DL) flight with your mobile device starting 24 hours and ending 60 minutes before the scheduled departure time (depending on your departure city and destination) to receive a mobile boarding pass on your mobile device.
You need to check in with the operating airline of the first flight in your trip. If your first flight is operated by an airline other than Delta or Delta Connection and you are not able to check in on delta.com, you will be advised of the name of the airline where you need to check-in.isit delta.com from 24 hours to 30 minutes* prior to a domestic flight within the U.S. or 60 minutes* prior to an international flight, go to Check In, and follow the simple instructions. To access your itinerary, you will need one of the following: 1  A SkyMiles number and Password.