aviationstack.com Reviews 

Core scheduling api's (flightsFuture & timetable) are rate limited to 1 request per minute even with a subscription, so building a flight scheduling tool on top of this api is pointless. You will need to set up a job to periodically scrape their data if you really need these. If they had any idea what they were doing, they would charge a fixed rate per api call rather than set insane limits (see FlightStats). Duplicate data in several endpoints, API restrictions not mentioned in documentation, etc. Very slow support to fix issues. Pretty terrible, would not recommend.

Les données ne sont pas dutout fiable. Il me ressort 128 vols pour un jour où il y en a eu 70. Le support ne répond pas, même si on paye...

This company is a scam. They've gained permanent access to my card. Unfortunately, there's no option to attach files on Trustpilot, so I can't provide visual proof here. I recently tried signing up, and they accessed my card. I'm trying to remove/delete my card from this fraudulent website, but it's impossible because they've locked my card details and removed the option to delete it. Now, they're planning to charge me monthly. It's outright theft, not a legitimate business. Please avoid them to protect your card security. I have saved all the evidence, and I'm willing to show it to anyone interested. But please, don't put your cards at risk with them.

Absolute s**t show.
Bought the API on the understanding that it would have historical data. It was not made clear that this only goes back 3 months at a time. Extremely slow response times (if at all) and incomplete data sets.
Refused to issue a refund. Whatever you do, stay away from this company.

Absolutely horrid. Incorrect data returned by their /routes endpoint, no replies to emails or bug reports, and I can't cancel my subscription online. I've sent two emails now with no response about cancelling. Do NOT use. If you're looking for an alternative, use the FlightStats API, they've been great so far.

Update: I've now sent TEN emails, and they still haven't cancelled my subscription and there's no way to cancel it online. This is absolutely illegal and ridiculous.

Horrible API, the data is NOT real time and the customer service is horrible at best.

I actually want to give a zero rating. Lots of null values for their dataset and customer support is non-existent even after paying.

Before even paying, I asked about a technical question and Paul Wafula from APILayer's support responded that technical support is only for paid members. I sent him another email to at least help me reassure that the data I'm looking for exists and he ignored my next 2 emails. I should have seen this as a red flag but I took the benefit of the doubt that their support services would be tailored only for paid customers, which is a total lie.

I paid for the Basic Subscription plan ($49.99) and I realized that there were so many null values for aircraft details, arrival/departure timings, etc and the flight volumes are extremely inaccurate (returns 3 flights vs 50 flights for an airline at a specific airport that I wanted to use) and those returned flights have so many missing data. Historical flights are even worse - you can't even return any flight data at all!

I emailed about these problems 3 times and I still haven't received a response.

All of these complaints posts you are reading are 100% real. Do not use Aviationstack at all for your projects or services.

If they can resolve my issues, then I will gladly remove this negative review. If this review is still here, then you know what to do (or not to do, which is to sign up for their services in this case).

API is always down and you have to pay $39.99/month to get support.

1) The API was down for 5 days! without any explanation.
2) Errors in flights, data etc
3) API uptime is about 70%.
4) API status page is fake.
5) No support you have to wait days, months years for an answer.

Had to buy a subscription to test Historical Flight API. During the first 2 days the service was unavailable at all, returning mysql error instead of a dataset.
Later that was fixed, however, instead of a list of flights the service responds with an empty array for any date except +/- 2 days from now. For me that means they just fetch Flightstats free data without even saving it somewhere.

Asked Apilayer' support team about the issue a week ago, still waiting for an answer.
Also according to ToS there's no way to get a refund unless you bought a year long subscription plan.

Just get the same data from FlightStats and don't pay these scammers.

The real-time data is a blatant lie, with delays of several minutes and sometimes more than 10 minutes. Ten minutes, Carl! This is not real time data...
All the data is done in such a way that you have to request pages of limited size, which makes it impossible to build anything at all with your API. It's impossible to build at least an acceptable user experience on it.
Errors in flights, arrival schedules on the airport site show different times and statuses, and most importantly, departure cities! Wasted money...