Firework displays can be a hazard to aircraft. Sufficiently large firework displays are notified to aircraft operators through NOTAMs. The Canadian NOTAM Manual contains a specific section on fireworks and pyrotechnics (Section 5.5.10). Some displays may result in the establishment of restricted airspace, which would compel aircraft to route around it. Aircraft may also choose to avoid areas in which firework displays are happening.
However as Ryathal says, fireworks are in general forbidden near airports, and airliners cruise too high to be affected by regular firework displays. The NOTAMs mentioned above are more likely to affect smaller unscheduled aircraft. There might also be occasional suspensions of operation like the Manchester one described by him.