When is National Defense Transportation Day in United States?

May 1, Lei Day May 1, National Day of Prayer May 1, Loyalty Day May 1, Yom Ha'atzmaut May 1, Law Day May 2, World Tuna Day May 2, Kentucky Oaks May 3, World Press Freedom Day May 3, Kentucky Derby May 3, National Explosive Ordnance Disposal (EOD) Day May 4, Rhode Island Independence Day May 4, Kent State Shootings Remembrance May 5, Cinco de Mayo May 6, National Nurses Day May 8, Truman Day May 8, Time of Remembrance and Reconciliation for Those Who Lost Their Lives during the Second World War May 8, Victory in Europe Day May 8, World Ovarian Cancer Day May 9, Military Spouse Appreciation Day May 9, Confederate Memorial Day May 10, Confederate Memorial Day May 10, World Migratory Bird Day May 11, Mother's Day May 12, International Nurses Day May 15, International Day of Families May 15, Peace Officers Memorial Day May 16, Lag BaOmer May 16, National Defense Transportation Day May 17, World Information Society Day May 17, Preakness Stakes May 17, Armed Forces Day May 20, World Autoimmune / Autoinflammatory Arthritis Day May 21, Emergency Medical Services for Children Day May 21, World Day for Cultural Diversity for Dialogue and Development May 22, National Maritime Day May 22, Harvey Milk Day May 22, International Day for Biological Diversity May 23, International Day to End Obstetric Fistula May 25, National Missing Children's Day May 25, African Liberation Day May 26, Memorial Day May 26, Jefferson Davis' Birthday May 29, International Day of United Nations Peacekeepers May 29, Ascension Day May 31, World No Tobacco Day