Stuck on final SQL query

I’m busy creating a report and am stuck with how to structure the final query. I have a sub-query that returns the following result set

I need the final query result to look like this:

I know I can get there with an over engineered query, but would rather do it the right way, while also learning something new. Would really appreciate any help or suggestions. Thanks

PS Using Microsoft SQL Server 2014

Answer

Here is a sample of code that should do what you are expecting it to do.

CREATE TABLE #T (
    AircontractIDFK INT
    ,DepCity CHAR(3) 
    ,SeatsHeld INT
)

INSERT INTO #T(
    AircontractIDFK
    ,DepCity
    ,SeatsHeld
)
SELECT
    AircontractIDFK
    ,DepCity
    ,SeatsHeld
FROM
    (VALUES (1175, 'JFK', 29)
            ,(4385, 'CLT', 27)
            ,(4385, 'CVG', 2)
            ,(4389, 'ORD', 7)
            ,(4389, 'ORD', 24)) AS T (AircontractIDFK, DepCity, SeatsHeld)

;WITH CTE_T AS(
    SELECT
        AircontractIDFK
        ,DepCity
        ,SUM(SeatsHeld) AS SeatsHeld
    FROM
        #T
    GROUP BY
        AircontractIDFK
        ,DepCity
)
SELECT
    *
    ,STUFF((SELECT ',' + ST.DepCity + '(' + CAST(ST.SeatsHeld AS VARCHAR(10)) + ')' FROM CTE_T ST  WHERE ST.AircontractIDFK = T.AircontractIDFK  FOR XML PATH('')), 1,1,'')

FROM
    CTE_T T