Custodio earned a Bachelor of Arts degree from the University of Puerto Rico and worked for various industries before landing a job in the accounting department of Prinair (Puerto Rico International Airlines). There she met Edwin Custodio, with whom she would eventually have two children. She later worked for the US Department of Defense (DoD) in Panama. With the support of her husband, she presented herself before Headquarters, Air Force Military Personnel Center (AFMPC) to apply for the United States Air Force Officer Training School. Upon admission, Custodio was accepted as a pilot candidate to become a United States Air Force pilot.

She entered the Flight Screening Pilot Officer Training School in January 1980. After successful completion of Flight Screening she entered Officer Training School and was commissioned a Second Lieutenant. She qualified for Undergraduate Pilot Training (UPT) at Laughlin Air Force Base in Texas and graduated the following year, thus becoming the first Latina to complete the U.S. Air Force military pilot training.

Her first military assignment was that of instructor pilot at Laughlin AFB. She was the first female to become a Northrop T-38 Talon (T-38) UPT flight instructor at that base. The T-38 Talon is the Air Force’s two-seat, supersonic jet trainer. On one occasion a bird struck the engine of her plane in bad weather while she was in flight. She was able to overcome the emergency and safely land her plane. Because of this she was recognized by the Air Force, and awarded the HQ AETC Aviation Safety Award for superior airmanship.

Custodio was later assigned to Randolph Air Force Base where she was also the first female T-38 Instructor Pilot. During her career she also served as Pilot Instructor Training; T-41 Flight Screening – Operations Officer and Check Pilot.

Custodio retired from the Air Force with the rank of lieutenant colonel in October 2003, after serving in the military for 23 years and 10 months. Her last assignment as an Air Force Reserve officer was that of accountability and readiness the Directorate of Personnel, HQ USAF.

In June 1988, while she was serving in the US Air Force Reserve, she was hired by American Airlines as a commercial pilot. Custodio became one of the first Latina commercial airline captains. During her years with American, she flew various types of aircraft. She piloted the Boeing 727, Fokker 100, Boeing 757 and Boeing 767 to various countries in Europe, the Caribbean, Central America and South America. She also flew to Mexico, Canada and to various cities in the United States. Custodio retired from American Airlines in February 2008, with over 11,000 flight hours.

Custodio retired from the military after 24 years of service and lives in San Antonio, Texas, with her husband. There she founded “Dragonfly Productions LLC,” a production company that creates personal film documentaries. In 1992, she founded the Ballet Folklorico Borikèn, the Puerto Rican folk ballet.

Custodio is a Trustee of the Order of Daedalians Foundation, a Board Member and Treasurer for the Women in Aviation Alamo City Chapter and Board Member for the Dee Howard Foundation. Custodio also serves as vice president of the Hispanic Association of Aviation and Aerospace Professionals (HAAAP). These organizations inspire young students in the San Antonio and surrounding areas to seek civilian and military aviation careers. They hosts students to tour various airplanes and control towers and also speak to students in all grades to present career opportunities in aviation and aerospace.