Scraping kayak

Hi, I would like to scrape the Kayak website for airfares. The script would need to be able to run on a daily/hourly basis and find the cheapest fares for a given destination (for example: JFK-CDG) around certain dates. Input: airport of origin, airport of destination, departure date, return date, time window, maximum number of legs (for example, no more than 1 stop each way). The time window would be in days. If you set it to 3 for example, the program would search for fares up 3 to days before & after each date. That would be 49 date combinations if I'm not mistaken. Knowing the script would need to run on a daily/hourly basis, the main objective is to find the best time to book a fare. The output should be in an Excel file or something equivalent, and send an email with a recap of the cheapest fares *if* the price dropped significantly (set %) since the last scraping. Let's take an example. JFK to CDG (Paris, France). The fares average $800 for a given time period. Every day, the script scrapes Kayak and the cheapest fares fluctuate between $750 and $850. One day though, one of the fares drops to $600 --> an email is sent, because it's a 25% drop and the set percentage was 20% (the last price checked by the script was $800). I'm not sure if that makes sense and if there's a better way to do it. I'm open to discussion. That script could be in Python, PHP or any other language. I just want to be able to edit it later if I need to tweak it, so comments in the script are more than welcome. It does need to be able to be part of a cron job.