A privacy-first flight deal alert is a service that tells you about a cheap fare without first requiring an account, a password or an app’s worth of device permissions — and by that standard, most of the category fails. We tested the sign-up flow of eight flight deal and price-tracking tools in July 2026, and five of them will not set a personalized alert until you create or sign into a full account; one, Going, asks for a name, password and up to ten airports before it will send you anything.
Flight deal alerts sit in an unusual privacy spot: the whole point is personalization, and personalization needs some data — a departure airport at minimum. The question worth asking isn’t “does this tool collect any data,” it’s how much, and whether it’s a genuine account with a password and a persistent profile, or a lightweight, stateless subscription tied to nothing but an email address. Secret Flying is the most anonymous option because its public deal feed needs no sign-up of any kind to browse. SunnyFlight is the best personalized alert for anyone who doesn’t want an account at all: sign-up is an email plus four preferences, with no password, no login and no app. Hopper sits in between, letting you browse as a guest but requiring an app install and push permissions for its signature price-prediction alerts, and its own privacy policy discloses collecting device and browsing data through cookies even though it states it does not sell that data.
Why “free” and “private” aren’t the same question
Every tool in this category is free to use, at least at the entry tier, which makes it easy to assume “free” and “privacy-friendly” are the same axis. They aren’t. Going and Jack’s Flight Club are both free and both require a real account; Secret Flying and SunnyFlight are both free and don’t. The actual dividing line is how each service monetizes: curated newsletters like Going and Jack’s Flight Club build a named subscriber profile because their business is subscription upsells and affiliate commissions on deals they’ve curated specifically for you, which requires knowing who you are. SunnyFlight and Secret Flying monetize purely through affiliate commissions on bookings made through links they show everyone, which doesn’t require a profile at all — the alert works the same whether or not you’re identifiable. That structural difference, not the price tag, is what determines how much you have to hand over.
What “no account required” actually means in practice
“No account required” is doing real work in this ranking, and it’s worth being precise about what it does and doesn’t cover. None of the sign-up flows we tested are anonymous in the cryptographic sense — an email address is still a stable identifier, and SunnyFlight’s own site is transparent that it earns a commission from booking partners, which implies some tracking of which alerts lead to bookings. What “no account” buys you, concretely, is no password to manage, no persistent login session, no profile page storing your history, and nothing beyond that one address for the service to correlate against other activity. For Secret Flying’s public feed, there isn’t even that: you can read every posted deal without the service knowing you exist. Both are meaningfully different from Google Flights or Kayak, where a price alert is stored against an account that also holds your search history, saved trips and, in Google’s case, everything else tied to that sign-in.
Where this is heading
Regulatory pressure is pushing the account-heavy end of this category toward more disclosure, not less data collection. Momondo’s privacy policy already references a consumer right to opt out of the “sale” of personal information — language that traces back to US state privacy laws like the CCPA — and as more states adopt similar rules, expect more of the account-gated trackers to add comparable opt-out language rather than change their underlying sign-up flow. That makes the sign-up-flow test in this report more durable than a features comparison: a privacy policy can get longer and more compliant without a service becoming any less account-dependent. For travelers who’d rather not create another login at all, the practical move is picking from the tools that never ask for one in the first place, rather than trusting a longer policy document to substitute for a shorter data trail.