You can extract the <table> content, which is all stored in a set of <td> tags, as a string array and go from there.
You first need to use findElement and extractHTMLText on an htmlTree object.
You then can use reshape to arrange the data, then use array2table to convert to a table.
Here is one approach:
travel_data = webread('https://www.tsa.gov/coronavirus/passenger-throughput');
travel_data_tree = htmlTree(travel_data);
selector = "td";
subtrees = findElement(travel_data_tree,selector);
str = extractHTMLText(subtrees);
table_data = str(4:end); % first three elements are just the column names
reshape_ncols = 3;
reshape_nrows = length(table_data)/reshape_ncols;
table_data_reshaped = reshape(table_data,reshape_ncols,reshape_nrows)';
% Convert to table
traveler_data_table = array2table(table_data_reshaped,'VariableNames',["Date" "Travelers_Today" "Travelers_Last_Year"]); % I got lazy with VariableNames, I know.
% Convert data types from strings to appropriate types
traveler_data_table.Date = datetime(traveler_data_table.Date);
traveler_data_table.Travelers_Today = str2double(traveler_data_table.Travelers_Today);
traveler_data_table.Travelers_Last_Year = str2double(traveler_data_table.Travelers_Last_Year);
traveler_data_table.Traveler_Ratio = traveler_data_table.Travelers_Today ./ traveler_data_table.Travelers_Last_Year;
% Plot the results
figure
plot(traveler_data_table.Date,traveler_data_table.Traveler_Ratio)
title("TSA Traveler Ratio by Date (2020 vs. 2019)")
grid on
% Some more fun analysis
% When did it bottom out?
[min_ratio,idx] = min(traveler_data_table.Traveler_Ratio);
min_ratio_pct = 100*min_ratio;
min_date = traveler_data_table.Date(idx);
disp("The minimum traveler ratio of " + min_ratio_pct + "% occurred on " + string(min_date))
latest_pct = 100*traveler_data_table.Traveler_Ratio(1);
disp("The current ratio is " + latest_pct + "%")
