Switzerland's three main international airports — Zurich, Geneva and Basel — all handle pets on arrival routinely, and Swiss International Air Lines is the most consistently pet-friendly carrier flying in. Small pets can typically travel in the cabin up to about 8kg including the carrier, with the carrier needing to fit under the seat in front; larger pets usually travel in the hold, subject to the airline's own temperature and breed restrictions.
Book your pet's spot when you book your own ticket, not after — cabin pet allowances are capped per flight, and airlines will not guarantee a space arranged at the last minute. Fees vary by airline and route, so confirm the current price directly rather than relying on older figures.
As with most of Europe, cargo-hold travel for larger pets is usually paused during summer heat on many routes. If your dog is too large for the cabin and you're travelling in July or August, check the airline's seasonal embargo dates before booking.