The GET method returns at most 100 records at a time. You need to paginate through the responses in order to get all records that match your formula. Within a response, if there is an additional page of responses to fetch, you will see an offset parameter. You should use that offset to get the next page. The pseudo-code looks something like this:
# fetch a page of records from Airtable
results = airtable.get("base_id", "table_name", {"filterByFormula": "MY FILTLER"})
# get the offset parameter
offset = results['offset'];
# create an array to hold all results
all_results = results['records']
# while offset is not NULL,
# fetch the next page by providing the "offset" query parameter
while offset is not NULL:
results = airtable.get("base_id", "table_name", {"offset": offset})
offset = results['offset'];
all_results.append(results['records'])
