Born in Barcelona, Catalonia, Aitor joined FC Barcelona's youth school in 2002, aged six, after starting it out at PB Cinc Copes.[1] Released in 2006, he spent his youth at three other teams in the region – RCD Espanyol, CF Damm and UE Cornellà – before joining Barça's youth ranks towards the end of the 2013–14 season.[2][3]
After finishing his graduation, Aitor was promoted to the reserves in July 2015, after the club's relegation to Segunda División B.[4] He made his senior debut on 22 August of that year, replacingJoan Campins for the final 21 minutes of a 1–2 loss at former club Cornellà.[5]
Aitor scored his first senior goal on 5 September 2015, equalising in the 43rd minute against rivals RCD Espanyol B at the Ciutat Esportiva Dani Jarque, albeit in a 2–3 defeat.[6] On 11 October, he scored the only goal in a home success over CD Alcoyano.[7]
On 28 October 2015, Aitor made his first team debut, coming on as a 64th-minute substitute for fellow debutant Wilfrid Kaptoum in a 0–0 away draw against CF Villanovense, for the season's Copa del Rey.[8][9] He played all 90 minutes in the return leg at the Camp Nou, which Barcelona won 6–1 and proceeded to the next round.[10]
Villarreal and Sevilla
On 12 January 2016, despite being their top scorer with four goals as they fought a second successive relegation, Aitor's contract with Barcelona B was rescinded as part of a mid-season revolution; hours later he joined Villarreal CF, being again put into their B-team.[11] He made his La Liga debut on 28 August, replacing Nicola Sansone for the final three minutes of a goalless draw at Sevilla FC.[12]
Aitor moved abroad for the first time on 31 July 2018, signing a two-year deal for FC Twente of the Dutch Eerste Divisie.[15] He scored 13 times in his first season in the Netherlands, as the team won promotion to the Eredivisie as champions with three games to spare, adding three more in the KNVB Cup.[16] He netted seven goals in the 2019–20 top-flight campaign, which was voided due to the COVID-19 pandemic; this included two in a 3–1 home win over FC Utrecht on 1 September.[17]
Aitor scored eight goals and registered two assists in the first eight games of 2022–23 for the team from Athens.[23] On 17 September he scored the first hat-trick of his career, with all the goals of a home win over Giannina; the first two came from direct free kicks and the last after a long dribble.[24]