Otherwise, you will not get a boarding pass without showing that proof. Taking your question more literal: there is not necessarily a passport check at the gate. That happens on and off, depending seemingly on mood, airline, and time of the day. But there is always a check before you get a boarding pass.

Whether your passport is checked before boarding depends entirely on whether your flight is international or domestic. For international flights in 2026, your passport is checked multiple times: first at the check-in counter (or baggage drop), then at immigration/passport control, and finally by the gate agent right before you step onto the aircraft. This is a mandatory safety and legal requirement to ensure you have the correct travel documents and visas for your destination. For domestic flights (within the same country), you do not need a passport; any valid government-issued photo ID (like a driver's license or Aadhaar card in India) is sufficient. However, for "Trusted Traveler" programs like DigiYatra in India or TSA PreCheck in the U.S., your identity is verified biometrically (facial scan), which may bypass a manual ID check at certain points. Even with digital technology, you must always have your physical passport on your person for any flight that crosses a national border.