Alaina scored five goals and had one assist in helping lead the Fury to the national championship in 2006 plus added four goals and one assist in 2007. She scored seven goals and provided one assist in 2008 and was named WPSL Co-Player of the Week and BigAppleSoccer.com Player of the Week. Although she was switched to defense for much of 2009, she still scored two goals and had two assists in another national championship year. It was the foul against her that led to the only goal in the 1-0 victory over Ajax America in the final.

The South Hempstead resident grew up on Staten Island where she was the leading scorer among high school teams in that borough. Alaina helped Curtis High School advance to the New York City PSAL soccer semifinals for the first time in the school history. In both her Freshman and Sophomore years, she was a Staten Island Advance All-County Soccer selection.

Moving to Long Island, she was the leading scorer in goals and points for South Side High School, which won the State Class A Championship the two years that she played for the Lady Cyclones. South Side finished ranked the number one girls high school team across the United States in 2007. Alaina received Best Offensive Player Awards as well as All-Class A, All-Long Island, All-State and All-American. The honors continue as she received the Michael Clarke Award as Nassau County MVP and was voted New York State championship game MVP with three goals and one assist in the 4-2 win. At South Side, Alaina is a member of the International Baccalaureate Honor Program and has been inducted into the National Honor Society as well as the French National Honor Society. A LIJSL Scholarship helps fund her education at Boston College.

Beyar has also worn the red, white and blue of the United States Youth National Teams. In the LIJSL, she started with the Long Beach Stars, playing with them for four years, and has played for the Albertson Fury '89 for the past five years. Her younger sisters, Julie and Carly, also compete for the Albertson Fury teams. Paul Riley, her coach for the past several years, commented, "Alaina can change a game in an instant. Electric quick! Loves scoring goals and is very difficult to contain. First-class training habits and a true striker's mentality. Knows when and how to run big time!"