Aird was part of a Canadian under-15 camp in 2010 and played in a friendly against the US the same year. After moving to Scotland, the country of his parents birth, Aird made his debut for Scotland at under-17 level in a friendly international tournament in August 2011. In 2012, he made his debut in a UEFA competition for Scotland featuring in the UEFA Under 17 Championship qualifying campaign against Macedonia. In his final under-17 game, he scored against Denmark.

Aird signed as a youth for Rangers at the age of sixteen. Within a year at the club he worked his way from the under-17 squad to the under-19 squad, eventually making his first team debut during a 4–1 victory over Montrose in the Scottish Third Division on 23 September 2012. Aird was incorrectly listed as the goalkeeper by many media sources during a match against Elgin City in December 2012 when it was actually Neil Alexander. He scored his first goal for the club versus Queens Park at Hampden Park on 29 December 2012.

In his first competitive match of the 2013–14 season he scored the first goal for Rangers as a half-time substitute against Forfar Athletic in the League Cup, Rangers went on to lose 2–1. On 3 May 2014, after a 1–1 draw with Dunfermline Athletic, Aird was among the Rangers players who made history by becoming the first Rangers side in 115 years to go an entire league season unbeaten, during which they clinched the Scottish League One Championship.

In April 2014 it was reported that Aird was set to pledge his international allegiance to Canada and join the senior squad for friendlies against Bulgaria and Moldova in Austria the following month, a claim the player later refuted on his personal Twitter account by saying he was still undecided on his future. In May 2014 Aird joined a training camp in Florida with the Canadian Under-20 team in preparation for the 2015 CONCACAF U-20 Championship, the tournament which will serve as CONCACAF qualification for 2015 FIFA U-20 World Cup.

On 28 September 2015 it was reported on the official Rangers website that Aird had been called up by Canada for an October friendly against Ghana. Aird got his first senior international cap in the match coming on as a second-half substitute for Karl Ouimette in the eventual 1–1 draw on 13 October 2015. Aird scored his first goal for Canada against his ancestral Scotland in a 1–1 draw on 22 March 2017.

Aird joined Major League Soccer club Vancouver Whitecaps FC on a season-long loan on 29 January 2016. He made his debut against Montreal Impact on 7 March 2016.

On 18 January 2017, Aird signed for Falkirk of the Scottish Championship until the end of the end of the season after mutually agreeing to terminate his contract with Rangers.” He made his debut for Falkirk in a 2–0 defeat to Greenock Morton in the Scottish Cup. His first goal came against Ayr United in a 4–1 win on 11 March 2017. At the end of his contract in May 2017, Aird was released by the club.

Aird signed a one-year deal with Dunfermline Athletic on 3 August 2017, with the option of a further year.

On 1 June 2018, Aird signed a two-year contract with Dundee United. On 2 September 2019 he left Dundee United by mutal consent.

On 31 January 2019, Aird was sent out on loan to Dumfries club Queen of the South until 31 May 2019.

On 26 September 2019, Aird signed for Aberdeen club Cove Rangers until January 2020. He left the club shortly before the expiry of his contract after he was pictured gesturing towards opposition fans while supporting Rangers in an Old Firm match.

Aird joined Valour FC of the Canadian Premier League on 24 January 2020. He made his debut for Valour on August 16 in a 2–0 loss to Cavalry FC. Aird scored his first goal for Valour in the following game against Atlético Ottawa, netting a penalty on August 19.