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.
1 Need one of the following for checking in online-SkyMiles number and PIN, reservation number, e-ticket number on your ticket, or the credit card number used to pay for your ticket. 2  If you have luggage to check you can drop off your luggage at any curbside check in or baggage drop location.elta Airlines offers check in online. Let's go over the specifics of their web check in services: 1  Delta Airlines-Check in up to 24 hours prior to departure.