Because the letter "h" is not a vowel sound. But there are exemptions to the rule. If it is pronounced in vowel sound like for an example, "hour", an is should be used.
This is a very difficult question to answer because the hotel chains with the most hotels are not necessarily chains in the correct sense of the word. For example, Best Western has over 4,000 hotels...
Last time I went to Edmonton I decided to stay at the Mayfield Inn & Suites. They had parking, but I'm sure there are also other hotels that have parking as well. You would need to call the...