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 should arrive at the boarding gate at least 15 minutes before your departure time for a domestic flight and 45 minutes if you are traveling on an international flight. Baggage check-in time requirements vary by airport.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.