The general recommendation is to arrive at the airport:

• For domestic or European flights: about 2 hours before departure
• For international or intercontinental flights: about 3 hours before departure

Additional time should be added if:

• Checking bags
• Traveling during busy periods (holidays, weekends)
• Traveling with children or needing assistance
• The airport is large or unfamiliar

In some cases, arriving 1.5 to 2 hours early for domestic or European flights with no checked luggage may suffice, but it's safest to follow the 2-hour and 3-hour rules for most situations to allow enough time for check-in, security, and getting to the gate without stress.