JSFiddle - React, Tailwind, and code Playground

HTML

<div id="results"></div>

JavaScript

var data = {
"USA":[{"country":"Albuquerque (ABQ)"},
        {"country":"Allentown (ABE)"}
        ],
"Canada":{"country":"Calgary (YYC)"},
"Hawaii":{"country":"Honolulu International Apt (HNL)"}
};

    var results = document.getElementById('results');
    for(var obj in data) {
     results.innerHTML += obj;
     results.innerHTML += '<ul>';
    
    for(var country in data[obj]) {
       var objLen = data[obj].length;
        if(typeof objLen != 'undefined') {
            results.innerHTML += '<li>' + data[obj][country].country +"</li>";  
        } else {
          results.innerHTML += '<li>' + data[obj][country] +"</li>";   
        }
    }
    results.innerHTML += '</ul><hr />';
}